Intestinal nematodes of the family Thelastomatidae have no apparent pathological effect on their cockroach hosts. Galeb (1878) has shown experimentally that oxyurids eat the same food as the host insect and that if one starves them, by withholding food from the host, the oxyurids die and disappear. In other words, these worms are not parasites, in the sense that we use the term in this paper, but commensals. Dobrovolny and Ackert (1934) stated that "all observations seemed to indicate that the health, fertility and activity of the heavily infested cockroaches were comparable with those of the non-parasitised specimens."

Very few papers have dealt with the ecology of the oxyurid parasites of cockroaches. According to Galeb (1878), usually one species of nematode is found in a single cockroach, but sometimes two species live together in the same host (e.g., in Blatta orientalis and Polyphaga aegyptiaca) where they compete for food. Galeb claimed that Hammerschmidtiella diesingi would replace Leidynema appendiculata; he observed that H. diesingi surpassed L. appendiculata in numbers and the latter became uncommon in the intestines of the cockroaches. On the other hand, Sobolev (1937) found that 48 percent of his oriental cockroaches were infected with both of the above species of nematodes. The average number of both species was 7.5, and the maximum number was 97; the mean number of H. diesingi was 5.1 and the maximum 64; the mean number of L. appendiculata was 2.4 and the maximum 33. More than 40 nematodes were found in each cockroach of 1.3 percent of those examined. These results apparently contradict Galeb's conclusions inasmuch as the number of each species in mixed infections was essentially the same as the number found in cockroaches infected by only one species (see pp. 195 and 197). Dobrovolny and Ackert (1934) found that 29 percent of 222 Periplaneta americana contained both of the above species of nematodes; whereas 40 percent contained L. appendiculata only, and 21 percent contained H. diesingi only. The infestation ranged from 1 to 36 worms per cockroach with averages of 3.8 per male, 5.1 per female, and 2.7 per nymph.

The eggs of some helminths pass unharmed through the guts of cockroaches that serve as vectors of these ova and have no effect on the insect. However, helminths that are secondary parasites in cockroaches damage the insect to varying degrees depending upon the extent of the infection. Thus the larvae of Moniliformis moniliformis pass through the gut wall and some may become embedded in the fat tissue (Moore, 1946). First stage larvae of Oxyspirura mansoni also burrow through the midgut wall into the fat body; Sanders (1929) believed that Pycnoscelus surinamensis could be killed if at one time a sufficient number of migrating larvae of O. mansoni penetrated the cockroach's intestinal wall. Gongylonema neoplasticum migrates through the digestive tract and encysts in the muscles of the thorax and legs of the host (Fibiger and Ditlevsen, 1914). Infective larvae of Protospirura muricola, after hatching from ingested eggs, pass through the cockroach's gut wall and encyst mainly in the thorax, around the crop, and at the bases of the large muscles of the prothoracic legs (Foster and Johnson, 1939). It is probably generally true that nematodes which are secondary parasites in cockroaches do some damage to the host's intestinal tract at least, and they probably also damage other organs in which they may encyst.

Cockroach tissues may react defensively to infections by parasitic nematodes. For example, encysted third-stage larvae of Physaloptera turgida have been found enclosed in a thin, brown, chitinous substance that was undoubtedly deposited by the tissue of the cockroach (Alicata, 1937). Cysts of similar appearance have been found in cockroaches infected with Physaloptera rara, P. maxillaris, P. hispida (Petri, 1950; Hobmaier, 1941; Schell, 1952), and Gongylonema pulchrum (Schell, 1952a); in the latter species the deposit eventually completely surrounded the nematode larva which was killed and "chitinized." Apparently these pigmented cysts surround unhealthy or dead larvae and are secreted as a defensive mechanism by the host (Schell, 1952a). Oswald (1958) has reported finding similar pigmented cysts in Blatta orientalis and Periplaneta americana that were experimentally infected with Rictularia coloradensis.

Our classification of the helminths follows Hyman (1951, 1951a).

HELMINTHS FOR WHICH COCKROACHES SERVE AS PRIMARY HOSTS

Phylum ASCHELMINTHES

Class NEMATODA

Order MERMITHOIDEA

Family MERMITHIDAE

Undetermined mermithids

Natural Hosts.—Ectobius pallidus, U.S.A., Plymouth, Massachusetts (Roth and Willis, 1957): This mermithid lies coiled in the body cavity of the host and one end may extend into the thorax. Apparently, the host is eventually killed and the worms may leave the cockroach ventrally between the thorax and abdomen (pl. 29, A) or thorax and head.

Periplaneta americana, Germany (Bode, 1936): Attacked by "Mermis" or "Gordius." It has been suggested that the name Mermis is often applied without critical identification to immature Nematoda found in insects (Buxton, 1955).

Order RHABDITOIDEA

Family DIPLOGASTERIDAE

Diplogastersp.

Synonymy.—Lycolaimus [Goodey, 1951].

Experimental Host.—Blattella germanica, U.S.A. (Christie and Crossman, 1933).

Family STEINERNEMATIDAE

Neoaplectanasp.

Experimental hosts.—Blattella germanica, Nauphoeta cinerea, and Periplaneta americana. U.S.A. (Dutky and Hough, 1955): This nematode, found in codling moth larvae, is close to Neoaplectana chresima Steiner but apparently is a new species. Nauphoeta cinerea was very susceptible to infection; B. germanica and P. americana were less susceptible.

Order OXYUROIDEA

Family THELASTOMATIDAE

These nematodes are found in the intestinal tract of cockroaches.

Aorurus philippinensisChitwood and Chitwood, 1934

Natural host.—Panesthia angustipennis, Philippine Islands (Chitwood and Chitwood, 1934).

Binema mirzaia(Basir, 1940) Basir, 1956

Synonymy.—Periplaneticola mirzaia Basir, 1940.

Natural host.—Periplaneta americana, India, Aligarh (Basir, 1940).

Blattelicola blattelicolaBasir, 1940

Natural host.—Blattella germanica, India, Aligarh (Basir, 1940).

Blatticola blattae(Graeffe, 1860) Chitwood, 1932

Synonymy.—Oxyuris blattae Graeffe, 1860; Oxyuris blatticola Galeb, 1878; Blatticola blatticola (Galeb, 1877) Schwenck, 1926 [Chitwood, 1930, 1932].

Natural hosts.—Blattella germanica, Brazil (PessÔa and CorrÊa, 1926; Schwenck, 1926); U.S.A. (Chitwood, 1930; Bozeman, 1942); Egypt? (Galeb, 1877, 1878); U.S.S.R. (Sobolev, 1937; Sondak, 1935); Czechoslovakia (Groschaft, 1956).

Ectobius lapponicus, Ectobius pallidus, Egypt? (Galeb, 1877, 1878).

Polyphaga aegyptiaca, France (Graeffe, 1860).

The life cycle has been studied by Bozeman (1942): He found never more than four worms in the large intestine of each cockroach. Embryos developed to "resting" stage in vitro. The resting stage was infective while the active stage was not. The worms seemed to have no effect on the vital activities of the host. Alicata (1934b) found that the embryo undergoes a molt before hatching.

Chitwood (1930) found 75 percent of the German cockroaches examined from houses in Washington infected. As a rule, one adult female, one or two males, and possibly two larval females are found in a single individual, apparently only in the rectum.

Sobolev (1937) found 72 percent of Blattella germanica collected in Gorkov (U.S.S.R.) infected with Blatticola blattae. The mean number of worms per host was 1.8, the maximum 5. Sondak (1935) found about 30 percent of 788 B. germanica collected in Leningrad to be infected with B. blattae. Groschaft (1956) regularly found only single worms in B. germanica, collected in a laboratory in Prague, except for two females that contained 2 and 3 worms each.

Blattophila sphaerolaimaCobb, 1920

Synonymy.—Aorurus sphaerolaima (Cobb, 1920) Travassos, 1929. Although Chitwood (1932) indicated that the taxonomic position of this nematode is questionable, Chitwood and Chitwood, 1934, apparently accepted it as a valid species in describing the variety javanica.

Natural host.—Panesthia laevicollis [Cobb recorded the host as Panesthia brevicollis, but no such cockroach exists. Van Zwaluwenburg (1928) and Caudell (in Chitwood, 1932) believed that Cobb meant Panesthia laevicollis. According to Gurney (personal communication, 1957) Caudell's notes show that in 1933 he wrote to Dr. Chitwood and explained that he had compared Cobb's figure of the cockroach with laevicollis Saussure (figures and description) and had found them the same.] Australia, New South Wales (Cobb, 1920).

Blattophila sphaerolaima var. javanicaChitwood and Chitwood, 1934

Natural host.—Panesthia angustipennis, Philippine Islands (Chitwood and Chitwood, 1934).

Blattophila supellaimaBasir, 1941

Natural host.—Supella supellectilium, India, Aligarh (Basir, 1941).

Cephalobellus brevicaudatum(Leidy, 1851) Christie, 1933

Synonymy.—Thelastoma brevicaudatum Leidy, 1851 [Christie, 1933]. Thelastoma indiana Basir, 1940 [Basir, 1949].

Natural host.—Leucophaea sp., India, Aligarh (Basir, 1940, 1949).

Cephalobellus magalhaesi(Schwenck, 1926) Basir, 1956

Synonymy.—Bulh?esi magalhaesi Schwenck, 1926; Thelastoma magalhaesi (Schwenck, 1926) Travassos, 1929 [Basir, 1956].

Natural host.—"Barata selvagem," Brazil, SÃo Paulo (Schwenck, 1926).

Euryconema paradisaChitwood, 1932

Natural host.—Eurycotis floridana, U.S.A., Florida (Chitwood, 1932).

Galebia aegyptiaca(Galeb, 1878) Chitwood, 1932

Synonymy.—Oxyuris aegyptiaca Galeb, 1878; Blatticola aegyptiaca (Galeb, 1878) Schwenck, 1926 [Chitwood, 1932].

Natural hosts.—Blattella germanica, Brazil (Schwenck, 1926).

Polyphaga aegyptiaca, Egypt? (Galeb, 1878).

Hammerschmidtiella diesingi(Hammerschmidt, 1838) Chitwood, 1932

Synonymy.—Anguillula macrura Diesing, 1851; Aorurus diesingi (Hammerschmidt, 1838) Travassos, 1929; Streptostomum gracile Leidy, 1850; Oxyuris diesingi Hammerschmidt, 1838; Oxyuris blattae orientalis Hammerschmidt, 1838 [Chitwood, 1932]. Oxyuris macrura of Lankester (1865).

Natural hosts.—Blatta orientalis, Europe (Hammerschmidt 1838, 1847; BÜtschli, 1871); Egypt? (Galeb, 1878); England (Lankester, 1865; Lee, 1958); U.S.A. (Leidy, 1850a); U.S.S.R. (Yakimov and Miller, 1922; Sobolev, 1937; Sondak, 1935); Brazil (Travassos, 1929); China (Chitwood, 1932); Czechoslovakia (Groschaft, 1956).

Leucophaea maderae, Brazil (PessÔa and CorrÊa, 1926).

Periplaneta americana, Brazil (MagalhÃes, 1900; PessÔa and CorrÊa, 1926). U.S.A.: Texas (Todd, 1943); Kansas (Dobrovolny, 1933; Dobrovolny and Ackert, 1934); North Carolina (Hatcher, 1939); Iowa, North Dakota, Michigan (Hoffman, 1953). China (Chitwood, 1932). India (Basir, 1940). Czechoslovakia (Groschaft, 1956). England (Lee, 1958).

Periplaneta australasiae, Brazil (PessÔa and CorrÊa, 1926).

Polyphaga aegyptiaca (Linstow, 1878).

Cockroaches (Blatta orientalis, Blattella germanica, and/or Periplaneta americana), U.S.A. (McAdow, 1931).

Cockroach, Venezuela (Tejera, 1926).

According to Hammerschmidt (1847) this worm may be found throughout the intestinal canal but especially in the small intestine. It is frequently found in adults and seldom in the nymphs. There were seldom more than 5 to 10 worms in one cockroach and female worms were found more frequently than males; the male worms were found only in winter and spring while the females were present at all times of the year. BÜtschli (1871) stated that all stages from those just hatching to mature males and females are found.

Yakimov and Miller (1922) found H. diesingi in 50.8 percent of 124 B. orientalis collected in Petrograd. Sobolev (1937) found 96 percent of B. orientalis infected with H. diesingi with a mean number of 5.6 and maximum number of 22 in one cockroach. Groschaft (1956) found 18 in one specimen of B. orientalis. Dobrovolny and Ackert (1934) found about 50 percent of 222 P. americana infected with H. diesingi. Sondak (1935) found about 36 percent of 412 B. orientalis infected with either or both H. diesingi and Leidynema appendiculata.

Two molts occur during development of the eggs; the first takes place outside the host resulting in a resting or infective stage. After the egg in the infective stage is eaten by the host, the second molt occurs before the egg hatches. Completion of the second molt and hatching perhaps are connected with ammonia present in the digestive tract; the ammonia seems to arise from the bacteria present in the gut. There appears to be a relationship between the intestinal bacteria of the cockroach and development and hatching of nematode eggs (Todd, 1944).

At the time of oviposition the nematode eggs are in the very earliest stages of cleavage. In 36 hours a motile, tadpole-like stage is reached and in a few days the embryo becomes quiescent and nonmotile. This nonmotile stage is infective whereas the motile embryonic stage is not. Feeding experiments proved that transmission of the nematode is direct. The worm reaches sexual maturity in 20 or 30 days after being ingested by the cockroach (Dobrovolny, 1933).

The bacterium Streptomyces leidynematis Hoffman grows on the cuticle of H. diesingi (Hoffman, 1953). The bacterium apparently is only anchored to the nematode and probably obtains its food from the intestinal contents of the cockroach. See notes under Leidynema appendiculata.

Hammerschmidtiella neyraiSerrano SÁnchez, 1945

Synonymy.—Hammerschmidtiella neyrae Serrano SÁnchez, 1947. [According to M. B. Chitwood, personal communication, 1957, Serrano SÁnchez's emendation is apparently an error.]

Natural host.—Blatta orientalis, Spain, Grenada (Serrano SÁnchez, 1947): Of 2,943 specimens examined, 1,143 were parasitized by oxyurids and of these 45 percent contained H. neyrai.

Leidynema appendiculata(Leidy, 1850) Chitwood, 1932

Synonymy.—Oxyuris blattae orientalis Hammerschmidt, 1847, of BÜtschli, 1871, and Oxyuris blattae-orientalis of MagalhÃes, 1900; Oxyuris blattae Hammerschmidt, 1847, of Galeb, 1878; Aorurus (Thelastoma) appendiculatus Leidy, 1850. [Chitwood, 1932.] Serrano SÁnchez (1947) has divided this species into three geographical varieties as follows: L. appendiculata (Leidy, 1852) (Dobrovolny and Ackert, 1934) var. indiana; L. appendiculata (Leidy, 1852) (Chitwood, 1932) var. americana; L. appendiculata (Serrano SÁnchez, 1947) var. hispana. However, Basir (1956) does not recognize these varieties. The Russians recognize hispana (M. B. Chitwood, personal communication, 1957).

Natural hosts.—Blaberus atropos, South America (Chitwood, 1932).

Blatta orientalis, Egypt? (Galeb, 1878); Europe (BÜtschli, 1871); U.S.S.R. (Sobolev, 1937; Sondak, 1935); U.S.A., Nebraska (Todd, 1944); Spain (Serrano SÁnchez, 1947): Recorded as var. hispana. Czechoslovakia (Groschaft, 1956). England (Lee, 1958a).

Blatta orientalis or Periplaneta americana, Brazil (MagalhÃes, 1900).

Periplaneta americana, U.S.A.: Texas (Todd, 1943); Nebraska (Todd, 1944); Kansas (Dobrovolny, 1933; Dobrovolny and Ackert, 1934); North Carolina (Hatcher, 1939); Iowa, North Dakota, Michigan (Hoffman, 1953). Czechoslovakia (Groschaft, 1956). England (Lee, 1958a).

Cockroach, Venezuela (Tejera, 1926).

Cockroaches (Blatta orientalis, Blattella germanica, and/or Periplaneta americana), U.S.A. (McAdow, 1931).

Chitwood (1932) also listed China for distribution of the worm, but we could not tell which host was involved.

The worms are found in the colon and rectum of the host. Galeb (1878) found as many as 20 individuals in a single B. orientalis. Sobolev (1937) found 52 percent of B. orientalis infected with L. appendiculata; the mean number of worms per roach was 1.5 and the maximum 2. Dobrovolny and Ackert (1934) found 69 percent of 222 P. americana infected with this species.

Two molts occur within the egg during development of the larva. The first molt occurs outside the host resulting in the formation of an infective resting stage. The second molt occurs inside the cockroach (Todd, 1941, 1944).

Transmission of the nematode is direct, eggs in the resting embryonated stage being infective (Dobrovolny and Ackert, 1934).

Hoffman (1953) described a filamentous bacterium, Streptomyces leidynematis Hoffman, which grows on the cuticle of L. appendiculata in P. americana. Leidy (1853) noted the presence of simple, inarticulate, amorphous filaments, growing from nematodes infecting B. orientalis. BÜtschli (1871) and MagalhÃes (1900) described similar filaments adhering to the surface of oxyurids from cockroaches.

Leidynema appendiculata(Leidy, 1850) Chitwood, 1932?

Natural host.—Eurycotis floridana, U.S.A., Massachusetts (Roth and Willis, unpublished data, 1955): Determined by Dr. G. Steiner who wrote us, "In Eurycotis floridana there were ten specimens of the nematode Leidynema appendiculata (Leidy, 1850). This cockroach is obviously a new host for this nematode. I am not sure that the nematode exactly agrees with the description as given in the literature."

Leidynema craniferaChitwood, 1932

Natural hosts.—Blaberus craniifer, U.S.A., Florida (Chitwood, 1932); Massachusetts (Roth and Willis, unpublished data, 1955). Determined by Dr. G. Steiner.

Blaberus atropos?, U.S.A., Florida (Chitwood, 1932): B. craniifer has generally been recorded as B. atropos of Stoll which is a closely related but distinct South American species (Rehn and Hebard, 1927).

Leidynema delatorreiChitwood, 1932

Natural host.—Leucophaea maderae, Cuba, Havana (Chitwood, 1932).

Leidynema nocalumChitwood and Chitwood, 1934

Natural host.—Panesthia angustipennis, Philippine Islands (Chitwood and Chitwood, 1934).

Leidynemella fusiformisCobb, 1934

Natural hosts.—Panesthia laevicollis?, Philippine Islands (Cobb in Chitwood and Chitwood, 1934).

Panesthia angustipennis, Philippine Islands (Chitwood and Chitwood, 1934).

Leidynemella panesthiae(Galeb, 1878) Chitwood and Chitwood, 1934

Synonymy.—Oxyuris panesthiae Galeb, 1878, in part; Thelastoma panesthiae (Galeb, 1878) Travassos, 1929. [Chitwood, 1932; Chitwood and Chitwood, 1934.]

Natural host.—Panesthia sp., New Guinea (Galeb, 1878): About 40 nematodes may be found in one insect.

Leidynemella paracraniferaChitwood and Chitwood, 1934

Natural host.—Panesthia angustipennis, Philippine Islands (Chitwood and Chitwood, 1934).

Oxyuris (?) heterogamiaeGaleb, 1878

Synonymy.—Thelastoma heterogamiae (Galeb, 1878) Travassos, 1929. The taxonomic position of this species is questionable; it might possibly belong in Blatticola or Protrellina (Chitwood, 1932). Basir (1956) placed it in an appendix to the family Thelastomatidae.

Natural host.—Polyphaga aegyptiaca, Egypt? (Galeb, 1878).

Protrelleta floridanaChitwood, 1932

Natural host.—Blaberus craniifer, U.S.A., Florida (Chitwood, 1932).

Protrellus aureusCobb, 1920

Synonymy.—The taxonomic position of this nematode is questionable (Chitwood, 1932).

Natural host.—Polyzosteria melanaria?, Australia, New South Wales (Cobb, 1920). [Caudell (in Chitwood, 1932) stated that this host was probably Platyzosteria analis.]

Protrellus aurifluus(Chitwood, 1932) Chitwood, 1933

Synonymy.—Protrellina aurifluus Chitwood, 1932.

Natural hosts.—Parcoblatta lata, U.S.A., North Carolina, Maryland (Chitwood, 1932).

Parcoblatta uhleriana, North Carolina (Hatcher, 1939).

Protrellus australasiae(PessÔa and CorrÊa, 1926) Travassos, 1929

Synonymy.—Oxyuris australasiae PessÔa and CorrÊa, 1926; Protrellina australasiae (PessÔa and CorrÊa, 1926) Chitwood, 1932 [Chitwood, 1933].

Natural host.—Periplaneta australasiae, Brazil (PessÔa and CorrÊa, 1926, 1927).

Protrellus galebiSchwenck, 1926

Synonymy.—Protrellina galebi (Schwenck, 1926) Chitwood, 1932 [Chitwood, 1933].

Natural host.—"Barata selvagem," Brazil (Schwenck, 1926).

Protrellus kÜnckeli(Galeb, 1878) Travassos, 1929

Synonymy.—Oxyuris kÜnckeli Galeb, 1878; Protrellina kÜnckeli (Galeb, 1878) Chitwood, 1932 [Chitwood, 1933].

Natural hosts.—Periplaneta americana, Egypt? (Galeb, 1877, 1878.) [Chitwood (1932) questioned the determination of this host because he failed to find this nematode in a large number of specimens from U.S.A. and China.] Brazil (PessÔa and CorrÊa, 1926).

Periplaneta australasiae, Brazil (PessÔa and CorrÊa, 1926).

Protrellus manni(Chitwood, 1932) Chitwood, 1933

Synonymy.—Protrellina manni Chitwood, 1932.

Natural host.—Aglaopteryx diaphana, Cuba (Chitwood, 1932).

Protrellus phyllodromi(Basir, 1942) Basir, 1956

Synonymy.—Protrellina phyllodromi Basir, 1942.

Natural host.—Blattella humbertiana, India, Aligarh (Basir, 1942): Found in the rectum.

Protrelloides paradoxaChitwood, 1932

Natural host.—Eurycotis floridana, U.S.A., Florida (Chitwood, 1932).

Schwenkiella icemi(Schwenck, 1926) Basir, 1956

Synonymy.—BulhÕesia icemi Schwenck, 1926; Thelastoma icemi (Schwenck, 1926) Travassos, 1929; Thelastoma aligarhica Basir, 1940. [Basir, 1956.]

Natural hosts.—"Barata selvagem," Brazil, SÃo Paulo (Schwenck, 1926).

Periplaneta americana, India, Aligarh (Basir, 1940); U.S.A., Nebraska (Todd, 1943).

Periplaneta brunnea, U.S.A., Louisiana (Todd, 1943).

Severianoia magnaPereira, 1935

Natural host.—"Blattidae sylvestres," Brazil (Pereira, 1935).

Severianoia severianoi(Schwenck, 1926) Travassos, 1929

Synonymy.—BulhÕesia severianoi Schwenck, 1926 [Travassos, 1929].

Natural hosts.—"Baratas de pau podre," Brazil (Schwenck, 1926).

Pycnoscelus surinamensis, U.S.A., Florida (Chitwood, 1932).

Suifunema caudelliChitwood 1932

Natural host.—Steleopyga? sinensis, Asia: Suifu, Szchuen, China (Chitwood, 1932).

Thelastoma pachyjuli(Parona, 1896) Travassos, 1929

Synonymy.—Oxyuris bulhÕesi de MagalhÃes, 1900; BulhÕesia bulhÕesi (MagalhÃes, 1900) Schwenck, 1926 [Travassos, 1929; Chitwood, 1932]; Thelastoma bulhÕesi (MagalhÃes, 1900) Travassos, 1929; although this last combination (from Chitwood, 1932) is not given by Basir (1956), it is implied by the synonymy that he does cite under T. pachyjuli.

Natural hosts.—Blatta orientalis, Czechoslovakia (Groschaft, 1956).

Periplaneta americana, Brazil (MagalhÃes, 1900); North America (Chitwood, 1932); U.S.A., North Carolina (Hatcher, 1939).

Thelastoma palmettumChitwood and Chitwood, 1934

Natural host.—Panesthia angustipennis, Philippine Islands (Chitwood and Chitwood, 1934).

Thelastoma riveroiChitwood, 1932

Natural host.—Periplaneta sp., Cuba (Chitwood, 1932).

Undetermined nematodes

Natural host.—Cutilia sp. near sedilloti, U.S.A. (hosts imported from New Zealand) (Roth, unpublished data, 1957).

Class NEMATOMORPHA

Order GORDIOIDEA

The immature stages of the following gordian worms have been found in the body cavity of cockroaches.

Family CHORDODIDAE

Chordodes morganiMontgomery, 1898

Synonymy.—Chordotes [sic] puerilis Montgomery, 1898 [Ward, 1918].

Natural host.—Cockroach, U.S.A. (Montgomery, 1898); Pennsylvania, Maryland, Michigan, Ohio, Florida, Iowa, Nebraska (Ward, 1918).

Family GORDIIDAE

Gordius aquaticusLinnaeus, 1758

Natural host.—Blatta sp., U.S.A. (Stiles and Hassall, 1894).

Leidy (1879) identified a 9-inch-long nematode which came from a cockroach (Blatta orientalis?) as probably being Gordius aquaticus. Ransom (in Pierce, 1921) states that G. aquaticus may be an accidental parasite of man. Faust (1955) summarizes the few reported cases of human parasitism. Dorier (1930) reported that the regurgitated liquid of Blatta orientalis had no effect on cysts of G. aquaticus after one hour.

Gordius blattae orientalisDiesing, 1851

Synonymy.—Gordius orientalis of Lankester (1865).

Natural host.—Blatta orientalis, Germany (Siebold, 1842; Linstow, 1878): Found in abdomen. Von Siebold called this "Filarien" but did not otherwise name or describe the worm.

Gordius pilosus(MÖbius, 1855) Diesing, 1861

Synonymy.—Chordodes pilosus MÖbius, 1855 [Diesing, 1861.]

Natural host.—Blaberus giganteus, Venezuela (MÖbius, 1855): From the insect's abdomen.

Gordiussp.

Natural hosts.—Periplaneta americana, South Africa (Porter, 1930); Germany (Bode, 1936): Bode's record may have referred to a Mermis or other nematode.

Cockroaches, Venezuela (Miall and Denny, 1886; Burr, 1899a; Tejera, 1926).

Parachordodes raphaelis(Camerano, 1893) Camerano, 1897

Synonymy.—Gordius raphaelis Camerano, 1893 [Camerano, 1897].

Natural hosts.—Symploce parenthesis and Kuchinga hemerobina, French Equatorial Africa (Camerano, 1893, 1897).

Undetermined gordian worms

Natural hosts.—Eurycotis floridana, Florida (T. Eisner, personal communication, 1958): See plate 29, B.

Parahormetica bilobata, Brazil (PessÔa and CorrÊa, 1929): Worm referred to as "gordiaceo."

Cockroaches, Australia (E. F. Riek, personal communication, 1953): Three undescribed gordian worms were found in undetermined cockroaches of the subfamily Blattinae.

HELMINTHS[4] FOR WHICH COCKROACHES SERVE AS INTERMEDIATE HOSTS

The use of the asterisk (*) is explained in footnote 3, page 4.

Phylum ACANTHOCEPHALA

Order ARCHIACANTHOCEPHALA

Family OLIGACANTHORHYNCHIDAE

* Prosthenorchis elegans(Diesing, 1851) Travassos, 1915

Natural host.—Blattella germanica, France (Brumpt and Urbain, 1938, 1938a; Brumpt et al., 1939).

Experimental hosts.—Blaberus atropos and Leucophaea maderae, France (Brumpt and Desportes, 1938).

* Prosthenorchis spirula(Olfers in Rudolphi, 1819) Travassos, 1917

Natural host.—Blattella germanica, France (Brumpt and Urbain, 1938, 1938a; Brumpt et al., 1939); Netherlands (Thiel and Wiegand Bruss, 1946).

Experimental hosts.—Blattella germanica, Netherlands (Thiel and Wiegand Bruss, 1946).

Blaberus atropos and Leucophaea maderae, France (Brumpt and Desportes, 1938).

Family MONILIFORMIDAE

* Moniliformis dubiusMeyer, 1932

Natural hosts.—Periplaneta americana, Brazil (MagalhÃes, 1898; Travassos, 1917); Gold Coast (Southwell, 1922); India (Pujatti, 1950); U.S.A. (Burlingame and Chandler, 1941; Moore, 1946).

Periplaneta australasiae, India (Pujatti, 1950).

Experimental hosts.—Blattella germanica, Japan (Yamaguti and Miyata, 1942).

Periplaneta americana, U.S.A. (Chandler, 1941; Moore, 1946); Japan (Yamaguti and Miyata, 1942).

* Moniliformis kalahariensisMeyer, 1931

Natural host.—Blattella germanica, India (Meyer, 1931, 1932).

* Moniliformis moniliformis(Bremser in Rudolphi, 1819) Travassos, 1915

Natural hosts.—Periplaneta americana, Argentina (Bacigalupo, 1927, 1927a, 1928); Brazil (PessÔa and CorrÊa, 1929); Algeria (Seurat, 1912); Burma (Subramanian, 1927); South Africa (Porter, 1930); Madras (Sita, 1949).

Periplaneta spp., New Caledonia (Rageau, 1956).

Cockroaches, Venezuela (Tejera, 1926).

Experimental hosts.—Blaberus atropos, Blatta orientalis, Blattella germanica, Leucophaea maderae, France (Brumpt and Urbain, 1938a).

Periplaneta americana, Japan (Yamaguti and Miyata, 1942); France (Brumpt, 1949); Madras (Sita, 1949).

Phylum ASCHELMINTHES

Class NEMATODA

Order OXYUROIDEA

Family SUBULURIDAE

* Subulura jacchi(Diesing, 1861) Railliet and Henry, 1914

Synonymy.—Subulura jacchi (Marcel, 1857) [Dr. J. T. Lucker, personal communication, 1957].

Experimental host.—Blaberus atropos, France (Chabaud and LariviÈre, 1955).

Order SPIRUROIDEA

Family THELAZIIDAE

* Oxyspirura mansoni(Cobbold, 1879) Ransom, 1904

Natural hosts.—Pycnoscelus surinamensis, Australia (Fielding, 1926, 1927, 1928, 1928a); U.S.A. (Sanders, 1927, 1928, 1929; Shealy, 1927); Formosa (Kobayashi, 1927); Antigua (Hutson, 1938, 1943); Hawaii (Illingworth, 1931; Schwabe, 1950, 1950a, 1950b, 1951); New Caledonia (Rageau, 1956).

We have recently found (Roth and Willis, 1960) that two strains of Pycnoscelus surinamensis exist; a parthenogenetic strain (from Florida), and a bisexual strain (from Hawaii) which does not reproduce parthenogenetically. The parthenogenetic strain is undoubtedly the form that has been shown to be the host of O. mansoni in the United States and Antigua, because only this form is found in the New World. Probably the parthenogenetic strain was the form involved in most Pacific areas. However, from internal evidence in his papers, we concluded that Schwabe, in Hawaii, may well have been working with the bisexual strain and possibly also with the parthenogenetic strain; if this is true, then both parthenogenetic and bisexual strains of Pycnoscelus surinamensis may serve as intermediate hosts of the eyeworm.

Experimental hosts.—Periplaneta americana, Antigua (Hutson, 1943).

Pycnoscelus surinamensis, U.S.A. (Sanders, 1929); Australia (Fielding, 1927, 1928a); Hawaii (Schwabe, 1951).

Rictularia coloradensisHall, 1916

Natural hosts.—Parcoblatta pensylvanica and Parcoblatta virginica, U.S.A., Ohio (Oswald, 1958): Of 49 wood roaches collected, one of each species contained a single larva each.

Experimental hosts.—Blatta orientalis, Blattella germanica, Parcoblatta pensylvanica, Parcoblatta virginica, Periplaneta americana, and Supella supellectilium, U.S.A. (Oswald, 1958): The larvae underwent normal development in all species of cockroaches except B. orientalis and P. americana in which cysts developed that contained a reddish-brown pigment; larvae in such cysts were dead or dying. Eggs of R. coloradensis hatched in the midgut of B. germanica and first-stage larvae entered the hindgut epithelium within 24 hours. The larvae underwent two molts within a cyst formed by tissues of the host's gut, the second molt occurring during the twelfth or thirteenth day. In Parcoblatta, cysts were found free in the body cavity as well as attached to the hindgut. In B. germanica and S. supellectilium the cysts remained attached to the hindgut. Usually over 20 cysts developed in each infected Parcoblatta; fewer than 10 per insect developed in the other species. Larvae became infective to the definitive host, the white-footed mouse [Peromyscus leucopus noveboracensis (Fischer)], as early as the tenth day.

Family SPIRURIDAE

* Agamospirura parahormeticaePessÔa and CorrÊa, 1929

Natural host.—Parahormetica bilobata, Brazil (PessÔa and CorrÊa, 1929).

* Gongylonema ingluvicolaRansom, 1904

Experimental host.—Blattella germanica, U.S.A. (Cram, 1935).

* Gongylonema neoplasticum(Fibiger and Ditlevsen, 1914) Ransom and Hall, 1916

Natural hosts.—Blatta orientalis, Netherlands (Baylis, 1925).

Blattella germanica, U.S.A. (Hitchcock and Bell, 1952).

Periplaneta americana, Denmark and St. Croix (Fibiger, 1913, 1913a; Fibiger and Ditlevsen, 1914); Netherlands (Baylis, 1925); Argentina (Bacigalupo, 1930); England (Leiper, 1926); South Africa (Porter, 1930); U.S.A. (Hitchcock and Bell, 1952); Formosa (Yokagawa, 1924, 1925, 1925a).

Periplaneta australasiae, Formosa (Yokagawa, 1924, 1925, 1925a).

Experimental hosts.—Blattella germanica, Denmark (Fibiger and Ditlevsen, 1914); U.S.A. (Hitchcock and Bell, 1952); France (Brumpt, 1949).

Blatta orientalis, Denmark (Fibiger and Ditlevsen, 1914).

Periplaneta americana, Denmark and St. Croix (Fibiger, 1913; Fibiger and Ditlevsen, 1914); U.S.A. (Hitchcock and Bell, 1952).

* Gongylonema pulchrumMolin, 1857

Experimental hosts.—Blattella germanica, U.S.A. (Ransom and Hall, 1915, 1916, 1917; Stiles and Baker, 1927; Schwartz and Lucker, 1931; Lucker, 1932; Alicata, 1934a, 1935); Europe (Baylis et al., 1925, 1926, 1926a; Sambon, 1926).

Parcoblatta sp., Alicata (1934, 1935).

* Gongylonemasp.

Natural host.—Periplaneta americana, Brazil (MagalhÃes, 1900); Algeria (Seurat, 1916); England? (Leiper, 1926).

* Microtetrameres helixCram, 1927

Experimental host.—Blattella germanica, U.S.A. (Cram, 1934).

* Protospirura bonneiOrtlepp, 1924

Natural host.—Leucophaea maderae, Venezuela (Brumpt, 1931).

Experimental hosts.—Blatta orientalis, Blattella germanica, Leucophaea maderae, France (Brumpt, 1931).

* Protospirura columbianaCram, 1926

Experimental host.—Blattella germanica, U.S.A. (Cram, 1926).

* Protospirura muricolaGeodoelst, 1916

Natural host.—Leucophaea maderae, Panama (Foster and Johnson, 1938, 1939).

* Seurocyrnea colini(Cram, 1927) Cram, 1931

Experimental host.—Blattella germanica, U.S.A. (Cram, 1931, 1931a, 1933a).

* Spirura gastrophila(MÜller, 1894) Seurat, 1913

Natural hosts.—Blatta orientalis, Europe? (Deslongchamps, 1824, in Seurat, 1911); Italy (Grassi, 1888); Algeria (Seurat, 1916).

Periplaneta americana, Brazil (PessÔa and CorrÊa, 1929).

Cockroach, Venezuela (Tejera, 1926).

Experimental hosts.—Blatta orientalis, France (Galeb, 1878a); "Cafards," Algeria (Roger, 1906, 1907).

* Tetrameres americanaCram, 1927

Natural host.—Blattella germanica, U.S.A. (Cram, 1931b, personal communication, 1956); Hawaii (Alicata, 1938, 1947).

Experimental host.—Blattella germanica, U.S.A. (Cram, 1931b).

* Tetrameres pattersoniCram, 1933

Experimental host.—Blattella germanica, U.S.A. (Cram, 1933).

Family PHYSALOPTERIDAE

* Physaloptera hispidaSchell, 1950

Experimental host.—Blattella germanica, U.S.A. (Schell, 1952, 1952a).

* Physaloptera maxillarisMolin, 1860

Experimental host.—Blattella germanica, U.S.A. (Hobmaier, 1941).

* Physaloptera praeputialisvon Linstow, 1889

Experimental host.—Blattella germanica, U.S.A. (Petri and Ameel, 1950).

* Physaloptera raraHall and Wigdor, 1918

Experimental host.—Blattella germanica, U.S.A. (Petri and Ameel, 1950; Petri, 1950).

* Physaloptera turgidaRudolphi, 1819

Experimental host.—Blattella germanica, U.S.A. (Alicata, 1937; Schell, 1952).

HELMINTHS WHOSE EGGS HAVE BEEN CARRIED BY COCKROACHES

The use of the asterisk (*) is explained in footnote 3, page 4.

Phylum PLATYHELMINTHES

Class TREMATODA

Order DIGENEA

Family SCHISTOSOMATIDAE

* Schistosoma haematobium(Bilharz, 1852) Weinland, 1858

Experimental vector.—Periplaneta americana, Gold Coast Colony (Macfie, 1922).

Class CESTODA

Order TAENIOIDEA

Family HYMENOLEPIDIDAE

* Hymenolepissp.

Natural vectors.—Periplaneta americana, Formosa (Morischita and Tsuchimochi, 1926).

Polyphaga saussurei, Tadzhikistan (Zmeev, 1936).

Family TAENIIDAE

* Taenia saginataGoeze, 1782

Experimental vector.—Periplaneta americana, Gold Coast Colony (Macfie, 1922).

Echinococcus granulosis(Batsch, 1786) Rudolphi, 1805

Synonymy.—Taenia echinococcus (Zeder, 1803) [Faust, 1939].

Experimental vector.—Periplaneta americana, Uruguay (PÉrez Fontana, 1955): Eggs were recovered from the feces of artificially infested cockroaches under "natural" conditions.

Family Unknown

* Undetermined tapeworm ova

Natural vector.—Polyphaga saussurei, Tadzhikistan (Zmeev, 1936).

Phylum ASCHELMINTHES

Class NEMATODA

Order OXYUROIDEA

Family OXYURIDAE

* Enterobius vermicularis(Linnaeus, 1758) Leach in Baird, 1853

Natural vectors.—Blatta orientalis and Blattella germanica, U.S.S.R. (Sondak, 1935).

Order ASCAROIDEA

Family ASCARIDAE

* Ascaris lumbricoidesLinnaeus, 1758

Natural vector.—Periplaneta americana, South Africa (Porter, 1930): The eggs may have been those of A. suum Goeze, 1782.

Experimental vectors.—Periplaneta americana, Gold Coast Colony (Macfie, 1922); India (Chandler, 1926).

Periplaneta americana, Periplaneta australasiae, Neostylopyga rhombifolia, Formosa (Morischita and Tsuchimochi, 1926).

* Ascarissp.

Natural vector.—Blatta orientalis, Italian Somaliland (Mariani and Besta, 1936).

Experimental vector.—Periplaneta americana, Uruguay (PÉrez Fontana, 1955): Eggs recovered from the insects' feces.

Order STRONGYLOIDEA

Family ANCYLOSTOMIDAE

* Ancylostoma caninum(Ercolani, 1859) Hall, 1913

Experimental vector.—Periplaneta americana, Netherlands (Akkerman, 1933).

* Ancylostoma ceylanicum(Looss, 1911) Leiper, 1915

Experimental vector.—Periplaneta americana, Gold Coast Colony (Macfie, 1922); Netherlands (Akkerman, 1933).

* Ancylostoma duodenale(Dubini, 1843) Creplin, 1845

Natural vector.—Periplaneta americana, South Africa (Porter, 1929, 1930).

Experimental vector.—Periplaneta americana, Gold Coast Colony (Macfie, 1922).

* Necator americanus(Stiles, 1902) Stiles, 1906

Natural vector.—Periplaneta americana, India (Chandler, 1926).

Experimental vector.—Periplaneta americana, Gold Coast Colony (Macfie, 1922).

* Hookworm ova

Experimental vectors.—Periplaneta americana, Periplaneta australasiae, Neostylopyga rhombifolia, Formosa (Morischita and Tsuchimochi, 1926).

Family TRICHOSTRONGYLIDAE

* Trichostrongylussp.

Natural vector.—Blatta orientalis, Italian Somaliland (Mariani and Besta, 1936).

Order TRICHUROIDEA

Family TRICHURIDAE

* Capillaria hepatica(Bancroft, 1893) Travassos, 1915

Experimental vector.—Blatta orientalis, Italy? (Giordano, 1950).

* Trichuris trichiura(Linnaeus, 1771) Stiles, 1901

Natural vectors.—Blatta orientalis, Italian Somaliland (Mariani and Besta, 1936); U.S.S.R. (Sondak, 1935).

Blattella germanica, U.S.S.R. (Sondak, 1935).

Periplaneta americana, Gold Coast Colony (Macfie, 1922); Formosa (Morischita and Tsuchimochi, 1926).

Experimental vectors.—Periplaneta americana, Gold Coast Colony (Macfie, 1922); India (Chandler, 1926); Uruguay (PÉrez Fontana, 1955).

Periplaneta americana, Periplaneta australasiae, and Neostylopyga rhombifolia, Formosa (Morischita and Tsuchimochi, 1926).

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