Coleoptera.

Sir John Lubbock, in his first paper on Bees and Wasps, quotes the following case from Kirby and Spence, with the remarks which I append:—

Catesby, however, says:—

BÜchner speaks of the fact that dung-beetles co-operate in their work as one that is well established, but gives no authorities or references.[91] A friend of my own, however, informs me that she has witnessed the fact; and in view of analogous observations made on other species of Coleoptera, I see no reason to doubt this one. Some of these observations I may here append.

Herr Gollitz writes to BÜchner thus:—

Similarly, there is no doubt that the burying beetles (Nicrophorus) co-operate.

Lastly, Clarville gives a case of a burying beetle which wanted to carry away a dead mouse, but, finding it too heavy for its unaided strength, went off, like the beetles previously mentioned, and brought four others to its assistance.[93]

A friend of Gleditsch fastened a dead toad, which he desired to dry, upon the top of an upright stick. The burying beetles were attracted by the smell, and finding that they could not reach the toad, they undermined the stick, so causing it to fall with the toad, which was then buried safe out of harm's way.[94]

A converse exemplification of beetle-intelligence is given by G. Berkeley.[95] He saw a beetle carrying a dead spider up a heath plant, and hanging it upon a twig of the heath in so secure a position, that when the insect had left it Mr. Berkeley found that a sharp shake of the heather would not bring the dead spider down. As the burying beetle preserves its treasure by hiding it out of sight below ground, so this beetle no doubt secured the same end but by other means; 'seeing,' as Mr. Berkeley observes, 'that if it did not hang up its prey, it might fall into the hands of other hunters, it took all possible pains to find out the best store-room for it.'

The above instances of beetle-intelligence lead me to credit the following, which has been communicated to me by Dr. Garraway, of Faversham. On a bank of moss in the Black Forest he saw a beetle alight with a caterpillar which it was carrying, and proceed to excavate a cylindrical hole in the peat, about an inch and a half deep, into which, when completed, it dropped the caterpillar, and then flew away through the pines. 'I was struck,' says my correspondent, 'with the creature's folly in leaving the whole uncovered, as every curious wayfaring insect would doubtless be tempted to enter therein. However, in about a minute the beetle returned, this time carrying a small pebble, of which there were none in the immediate vicinity, and having carefully fitted this into the aperture, fled away into space.'

Earwig.

I must devote a short division of this chapter to the earwig. M. Geer describes a regular process of incubation as practised by the mother insect. He placed one with her eggs in a box, and scattered the eggs on the floor of the latter. The earwig, however, carried them one by one into a certain part of the box, and then remained constantly sitting upon the heap without ever quitting it for a moment. When the eggs were hatched, the young earwigs kept close to their mother, following her about everywhere, and often running under her abdomen, just as chickens run under a hen.[96]

A young lady, who objects to her name being published, informs me that her two younger sisters (children) are in the habit of feeding every morning with sugar an earwig, which they call 'Tom,' and which crawls up a certain curtain regularly every day at the same hour, with the apparent expectation of getting its breakfast. This resembles analogous instances which, have been mentioned in the case of spiders.

Dipterous Insects.

The gad-fly, whose eggs are hatched out in the intestines of the horse, exhibits a singular refinement of instinct in depositing them upon those parts of the horse which the animal is most likely to lick. For, according to Bingley and other writers, 'the inside of the knee is the part on which these flies principally deposit their eggs; and next to this they fix them upon the sides, and the back part of the shoulder; but almost always in places liable to be licked by the tongue.' The female fly deposits her eggs while on the wing, or at least scarcely appears to settle when she extends her ovidepositor to touch the horse. She lays only a single egg at a time—flying away a short distance after having deposited one in order to prepare another, and so on.

The following anecdote, which I quote from Jesse, seems to indicate no small degree of intelligence on the part of the common house-fly—intelligence, for instance, the same both in kind and degree as that which was displayed by Sir John Lubbock's pet wasp already mentioned:

Crustacea.

There is no doubt that these are an intelligent group of animals, although I have been able to collect but wonderfully little information upon the subject. Mr. Moseley, F.R.S., in his very interesting work, 'Notes by a Naturalist on the Challenger,' says (p. 70):—

And again (pp. 48-9):—

The land crabs of the West Indies and North America descend from their mountain home in May and June, to deposit their spawn in the sea. They travel in such swarms that the roads and woods are covered with them. They migrate in a straight line, and rather than allow themselves to be deflected from it, 'they scale the houses, and surmount every other obstacle that lies in their way' (Kirby). They travel chiefly by night, and when they arrive at the sea-shore they 'bathe three or four different times,' and then 'commit their eggs to the waves.' They return to the mountains by the same route, but only the most vigorous survive the double journey.

Prof. Alex. Agassiz details some interesting observations on the behaviour of young hermit crabs reared by himself 'from very young stages,' when first presented with shells of mollusks. 'A number of shells, some of them empty, others with the animal living, were placed in a glass dish with the young crabs. Scarcely had the shells reached the bottom before the crabs made a rush for the shells, turned them round and round, invariably at the mouth, and soon a couple of the crabs decided to venture in, which they did with remarkable alacrity.' The crabs which obtained for their share the shells still inhabited by living mollusks, 'remained riding round upon the mouth of their future dwelling, and, on the death of the mollusk, which generally occurred soon after in captivity, commenced at once to tear out the animal, and having eaten him, proceeded to take its place within the shell.'[98]

There is a species of small crustacean (Podocerus capillatus) described by Mr. Bates, which builds a nest to contain its eggs. The nest is in the form of a hollow cone, built upon seaweed, and composed of fine thread-like material closely interlaced. 'These nests,' says Mr. Bates, 'are evidently used as a place of refuge and security, in which the parent protects and keeps her brood of young until they are old enough to be independent of the mother's care.'

Dr. Erasmus Darwin tells us, on the authority of a friend on whose competency as an observer he relied, that the common crab during the moulting season stations as sentinel an unmoulted or hard-shelled individual, to prevent marine enemies from injuring moulted individuals in their unprotected state. While thus mounting guard the hard-shelled crab is much more courageous than at other times, when he has only his own safety to consider. But these observations require to be corroborated.

In 'Nature' (xv., p. 415) there is a notice of a lobster (Homarus marinus) in the Rothesay Aquarium which attacked a flounder that was confined in the same tank with him, and having devoured a portion of his victim, buried the rest beneath a heap of shingle, on which he 'mounted guard.' 'Five times within two hours was the fish unearthed, and as often did the lobster shovel the gravel over it with his huge claws, each time ascending the pile and turning his bold defensive front to his companions.'

The following is quoted from Mr. Darwin's 'Descent of Man' (pp. 270-1):—

Mr. Darwin also alludes to the curious instinctive habits of the large shore-crab (Birgus latro), which feeds on fallen cocoa-nuts 'by tearing off the husk fibre by fibre; and it always begins at that end where the three eye-like depressions are situated. It then breaks through one of these eyes by hammering with its heavy front pincers, and turning round, extracts the albuminous core with its narrow posterior pincers.'

Remarkable cases occur of commensalism between certain crabs and sea-anemones, and they betoken much intelligence. Thus Professor MÖbius says in his 'BeitrÄge zur Meeresfauna der Insel Mauritius' (1880) that there are two crabs belonging to different genera which have the habit of firmly grasping a sea-anemone in each claw and carrying them about, presumably to secure some benefit to themselves. The more familiar case of the species of anemone which lives on the shells tenanted by hermit crabs is of special interest to us on account of a remarkable observation published by Mr. Gosse, F.R.S. (Zoologist, June, 1859). He found that on his detaching the anemone (Adamsia) from the shell, the hermit crab always took it up in its claws and held it against the shell 'for the space of ten minutes at a time, until fairly attached by a good strong base.' It was said by the late Dr. Robert Ball that when the common Sagartia parasitica is attached to a stone and a hermit crab is placed in its vicinity, the anemone will leave the stone and attach itself to the hermit's shell (Critic, March 24, 1860).

Intelligence of LarvÆ of Certain Insects.

I shall now allude to some of the more interesting facts touching the psychology of insects when in their immature or larval state. This is an interesting topic from the point of view which we occupy as evolutionists, because a caterpillar is really a locomotive and self-feeding embryo, whose entire mental constitution is destined to undergo a metamorphosis no less complete and profound than that which is also destined to take place in its corporeal structure. Yet although the caterpillar has an embryo psychology, its instincts and even intelligence often seem to be higher or more elaborated than is the case with the imago form. Where such is the case the explanation of course must be that it is of more importance to the species that the larval form should be in a certain measure intelligent than that the imago form should be so. Every larva is a potential imago, or breeding individual; therefore its life is of no less value to the species during its larval than during its adult existence; and if certain instincts or grades of intelligence are of more use to it during the former than during the latter period, of course natural selection would determine the unusual event which we seem here in some cases to see—namely, that the embryo should stand on a higher level of psychological development than the adult.

I may most fitly begin under this heading with the remarkable instincts of the so-called 'ant-lion,' which is the larva of a neuropterous insect, the common Myrmeleon (M. formicarium). I quote the following account of its habits from Thompson's 'Passions of Animals' (p. 258):—

The devices of the ant-lion are still more extraordinary if possible. He forms, with astonishing labour and perseverance, a pit in the shape of a funnel, in a dry sandy soil, under some old wall or other spot protected from the wind. His pit being finished, he buries himself among the sand at the bottom, leaving only his horns visible, and thus waits patiently for his prey. When an ant or any other small insect happens to walk on the edge of the hollow, it forces down some of the particles of sand, which gives the ant-lion notice of its presence. He immediately throws up the sand which covers his head to overwhelm the ant, and with its returning force brings it to the bottom. This he continues to do till the insect is overcome and falls between his horns. Every endeavour to escape, when once the incautious ant has stepped within the verge of the pit, is vain, for in all its attempts to climb the side the deceptive sand slips from under its feet, and every struggle precipitates it still lower. When within reach its enemy plunges the points of its jaws into its body, and having sucked out all its juices, throws out the empty skin to some distance.