He seized a short knife
and threw himself forward.

It was as if someone had thrown a bomb into a Quaker meeting, when adventure suddenly began to crowd itself into the life of the studious and methodical Leslie Larner, professor of entomology.

Fame had been his since early manhood, when he began to distinguish himself in several sciences, but the adventure and thrills he had longed for had always fallen to the lot of others.

His father, a college professor, had left him a good working brain and nothing else. Later his mother died and he was left with no relatives in the world, so far as he knew. So he gave his life over to study and hard work.

Still youthful at twenty-five, he was hoping that fate would "give him a break." It did.

He was in charge of a Government department having to do with Oriental beetles, Hessian flies, boll weevils and such, and it seemed his life had been just one bug after another. He took creeping, crawling things seriously and believed that, unless curbed, insects would some day crowd man off the earth. He sounded an alarm, but humanity was not disturbed. So Leslie Larner fell back on his microscope and concerned himself with saving cotton, wheat and other crops. His only diversion was fishing for the elusive rainbow trout.

He managed to spend a month each year in the Colorado Rockies angling for speckled beauties.

Larner was anything but a clock-watcher, but on a certain bright day in June he was seated in his laboratory doing just that.

"Just five minutes to go," he mused.

It was just 4:25 P. M. He had finished his work, put his affairs in order, and in five minutes would be free to leave on a much needed and well earned vacation. His bags were packed and at the station. His fishing tackle, the pride of his young life, was neatly rolled in oiled silk and stood near at hand.

"I'll just fill my calabash, take one more quiet smoke, and then for the mountains and freedom," he told himself. He settled back with his feet on his desk. He half closed his eyes in solid comfort. Then the bomb fell and exploded.

B-r-r-r-r!

The buzzer on his desk buzzed and his feet came off the desk and hit the floor with a thud. His eyes popped open and the calabash was immediately laid aside.

That buzzer usually meant business, and it would be his usual luck to have trouble crash in on him just as he was on the edge of a rainbow trout paradise.

A messenger was ushered into the room by an assistant. The boy handed him an envelope, said, "No answer," and departed.

Larner tore open the envelope lazily. He read and then re-read its contents, while a look of puzzled surprise disturbed his usually placid countenance. He spread the sheet of paper out on his desk, and for the tenth time he read:

That was all. It was enough. Larner lost his temper. He crumpled the paper and tossed it in the waste basket. He was not given to profanity, but he could say "Judas Priest" in a way that sizzled.

"Judas Priest!" he spluttered. "Anyone who would send a man a crazy bunch of nonsense like that, at a time like this, ought to be snuffed out like a beetle!

"'Meet you in the Frying Pan,'" he quoted. Then he happened to recall something. "By golly, there is a fishing district in Colorado known as the Frying Pan. That's not so crazy, but the planet Venus part surely is cuckoo."

He fished the paper out of the waste basket, found the envelope, placed the strange message within and put it in his inside coat pocket. Then he seized his suitcase and fishing tackle, and, rushing out, hailed a taxi. Not long after he was on his way west by plane.

As the country unrolled under him he retrieved the strange note from his pocket. He read it again and again. Then he examined the envelope. It was an ordinary one of good quality, designed for business rather than social usage. The note paper appeared quite different. It was unruled, pure white, and of a texture which might be described as pebbly. It was strongly made, and of a nature unlike any paper Larner had ever seen before. It appeared to have been made from a fiber rather than a pulp.

"Wonder who wrote it?" Larner asked himself. "It is beautiful handwriting, masculine yet artistic. Wonder where he got the Frying Pan idea? At any rate, I'm not going to the Frying Pan this year—I'm camping on Tennessee Creek, in Lake County, Colorado. The country there is more beautiful and restful.

"But this street address on the planet Venus. Seems to me I read somewhere that Marconi had received mysterious signals that he believed came from the planet Venus. Hesper, Hesper ... it sounds familiar, somehow. Wonder if there could be anything to it?"

Something impelled him to follow out the instructions in the note. He spent the next few hours repeating the address over and over again. When he was satisfied that he had memorized it thoroughly, he tore the strange paper into bits and sent it fluttering earthward like a tiny snowstorm.

Larner was not a gullible individual, but neither was he unimaginative. He was scientist enough to know that "the impossibilities of to-day are the accomplishments of to-morrow." So while not convinced that the note was a serious communication, still his mind was open.

The weird address insisted on creeping into his mind and driving out other thoughts, even those of his speckled playfellows, the rainbow trout.

"I've a notion to change my plans and go from Denver to the Frying Pan," he cogitated. Then he thought, "No, I won't take it that seriously."

Anyone who knows the Colorado Rockies knows paradise. There is no more beautiful country on the globe. Lake County, where Larner had chosen his fishing grounds, has as its seat the old mining camp of Leadville. It has been visited and settled more for its gold mines than the golden glow of its sunsets above the clouds, but the gold of the sunsets is eternal, while the gold of the mines is fading quickly away.

Leadville, with its 5,000 inhabitants, nestles above the clouds, at an altitude of more than 10,000 feet. Mount Massive with its three peaks lies back of the town in panorama and rises to a height of some 14,400 feet. In the rugged mountains thereabouts are hundreds of lakes fed by wild streams and bubbling crystal springs. All these lakes are above the clouds.

Winter sees the whole picture decorated with bizarre snowdrifts from twenty to forty feet deep, but spring comes early. The beautiful columbines and crocuses bloom before the snow is all off the ground in the valleys. The lands up to 12,000 feet altitude are carpeted with a light green grass and moss. Giant pines and dainty aspens, with their silvery bark and pinkish leaves blossom forth and whisper, while the eternal snows still linger in the higher rocky cliffs and peaks above.

Indian-paint blooms its blood red in contrast to the milder colorings. Blackbirds and bluebirds chatter and chipmunks chirp. The gold so hard to find in the mines glares from the skies. The hills cuddle in banks of snowy clouds, and above all a pure clear blue sky sweeps. The lakes and streams abound with rainbow trout, the gamest of any fresh water fish. It is indeed a paradise for either poet or sportsman.

In any direction near to Leadville a man can find Heaven and recreation and rest.

Finding himself on Harrison Avenue, the main street of the county seat, Larner, after renewing some old acquaintanceships, started west in a flivver for Tennessee Creek. The flivver is a modern adjustment. Until a few years ago the only means of traversing these same hills was by patient, sure-footed donkeys, which carried the pack while the wayfarer walked along beside.

The first day's fishing was good. Trout seemed to greet him cheerily and sprang eagerly to the fray. They bit at any sort of silken fly he cast.

The site chosen by Larner for his camp was in a mossy clearing separated from the stream by a fringe of willows along the creek. Then came a border of aspens backed by a forest of silver-tipped firs.

It was ideal and his eyes swept the scene with satisfaction. Then he began whittling bacon to grease his pan for frying trout over the open fire.

Suddenly he heard a rustle in the aspens, and, looking up, beheld a picture which made his eyes bulge. A man and a woman, garbed seemingly in the costumes of another world, walked toward him. Neither were more than five feet tall but were physically perfect, and marvelously pleasing to the eye. There was little difference in their dress.

Both wore helmets studded with what Larner believed to be sapphires. He learned later they were diamonds. Their clothing consisted of tight trouserlike garments surmounted by tunics of some white pelt resembling chamois save for color. A belt studded with precious stones encircled their waists. Artistic laced sandals graced their small firm feet.

Their skin was a pinkish white. Their every feature was perfection plus, and their bodies curved just enough wherever a curve should be. The woman was daintier and more fully developed, and her features were even more finely chiseled than the man. Otherwise it would have been difficult to distinguish their sex.

Larner took in these details subconsciously, for he was awed beyond expression. All he could do was to stand seemingly frozen, half bent over the campfire with his frying pan in his hand.

The man spoke.

"I hope we did not startle you," he said. "I thought my note would partly prepare you for this meeting. We expected to find you in the Frying Pan district. When you did not appear there we tuned our radio locator to your heart beats and in that way located you here. It was hardly a second's space-flying time from where we were."

Larner said nothing. He could only stand and gape.

"I do not wonder that you are surprised," said the strange little man. "I will explain that I am Nern Bela, of the City of Hesper, on the planet Venus. This is my sister Tula. We greet you in the interest of the Republic of Pana, which embraces all of the planet you know as Venus."

When Larner recovered his breath, he lost his temper.

"I don't know what circus you escaped from, but I crave solitude and I have no time to be bothered with fairy tales," he said with brutal bruskness.

Expressions of hurt surprise swept the countenances of his visitors.

The man spoke again:

"We are just what we assert we are, and our finding you was made necessary by a condition which grieves the souls of all the 900,000,000 inhabitants of Venus. We have come to plead with you to come with us and use your scientific knowledge to thwart a scourge which threatens the lives of millions of people."

There was a quiet dignity about the man and an air of pride about the woman which made Larner stop and think, or try to. He rubbed his hand over his brow and looked questioningly at the pair.

"If you are what you say you are, how did you get here?" he asked.

"We came in a targo, a space-flying ship, capable of doing 426,000 miles an hour. This is just 1200 times as fast as 355 miles an hour, the highest speed known on earth. Come with us and we will show you our ship." They looked at him appealingly, and both smiled a smile of wistful friendliness.

Larner, without a word, threw down his frying pan and followed them through the aspens. The brother and sister walking ahead of him gave his eyes a treat. He surveyed the perfect form of the girl. Her perfection was beyond his ken.

"They certainly are not of this world," he mused.

A few hundred yards farther on there was a beach of pebbles, where the stream had changed its course. On this plot sat a gigantic spherical machine of a glasslike material. It was about 300 feet in diameter and it was tapered on two sides into tees which Larner rightly took to be lights.

"This is a targo, our type of space-flyer," said Nern Bela. "It is capable of making two trips a year between Venus and the earth. We have visited this planet often, always landing in some mountain or jungle fastness as heretofore we did not desire earth-dwellers to know of our presence."

"Why not?" asked Larner, his mouth agape and his eyes protruding. His mind was so full of questions that he fairly blurted his first one.

"Because," said Bela, slowly and frankly, "because our race knows no sickness and we feared contagion, as your race has not yet learned to control its being."

"Oh," said Lamer thoughtfully. He realized that humans of the earth, whom he had always regarded as God's most perfect beings, were not so perfect after all.

"How do you people control your being, as you express it?" he asked.

"It is simple," was the reply. "For ninety centuries we have ceased to breed imperfection, crime and disease. We deprived no one of the pleasures of life, but only the most perfect mental and physical specimens of our people cared to have children. In other words, while we make no claim to controlling our sex habits, we do control results."

"Oh," said Larner again.

Nern Bela led the way to a door which opened into the side of the space-flyer near its base. "We have a crew of four men and four women," he said. "They handle the entire ship, with my sister and I in command, making six souls aboard in all."

"Why men and women?" thought Larner.

As if in answer to his thought Bela said:

"On the earth the two sexes have struggled for sex supremacy. This has thrown your civilization out of balance. On Venus we have struggled for sex equality and have accomplished it. This is a perfect balance. Man and women engage in all endeavor and share all favors and rewards alike."

"In war, too?" asked Larner.

"There has not been war on Venus for 600,000 years," said Bela. "There is only the one nation, and the people all live in perfect accord. Our only trouble in centuries is a dire peril which now threatens our people, and it is of this that I wish to talk to you more at length."

They were standing close to the targo. Larner was struck by the peculiar material of which it was constructed. There was a question in his eyes, and Nern Bela answered it:

"The metal is duranium; it is metalized quartz. It is frictionless, conducts no current or ray except repulsion and attraction ray NTR69X6 by which it is propelled. It is practically transparent, lighter than air and harder than a diamond. It is cast in moulds after being melted or, rather, fused.

"We use cold light which we produce by forcing oxygen through air tubes into a vat filled with the fat of a deep sea fish resembling your whale. You are aware, of course, that that is exactly how cold light is produced by the firefly, except for the fact that the firefly uses his own fat."

Larner was positively fascinated. He smoothed the metal of the targo in appreciation of its marvelous construction, but he longed most to see the curious light giving mechanism, for this was closer to his own line of entomology. He had always believed that the light giving organs of fireflys and deep-sea fishes could be reproduced mechanically.

The interior of the ship resembled in a vague way that of an ocean liner. It was controlled by an instrument board at which a man and a girl sat. They did not raise their heads as the three people entered.

When called by Bela and his sister, who seemed to give commands in unison, the crew assembled and were presented to the visitor.

"Earth-dwellers are not the curiosity to us that we seem to be to you," said Tula Bela, speaking for the first time and smiling sweetly.

Larner was too engrossed to note the remark further than to nod his head. He was lost in contemplation of these strange people, all garbed exactly alike and all surpassingly lovely to look upon.

An odor of food wafted from the galley, and Larner remembered he was hungry, with the hunger of health. He had swung his basket of fish over his shoulder when he left his campfire, and Tula took it from him.

"Would you like to have our chef prepare them for you?" she said, as she caught his hungry glance at his day's catch. This time Larner answered her.

"If you will pardon me," he said awkwardly. "Really I am famished."

"You will not miss your fish dinner," said the girl.

"I believe there is enough for all of us," said Larner. "I caught twenty beauties. I never knew fish to bite like that. Why, they—" and he was off on a voluminous discourse on a favorite subject.

Those assembled listened sympathetically. Then Tula took the fish, and soon the aroma of broiling trout mingled with the other entrancing galley odors.

After a dinner at which some weird yet satisfying viands were served and much unusual conversation indulged in, Nern Bela led the way to what appeared to be the captain's quarters. The crew and their visitor sat down to discuss a subject which proved to be of such a terrifying nature as to scar human souls.

"People on Venus," said Nern, as his eyes took on a worried expression, "are unable to leave their homes after nightfall due to some strange nocturnal beast which attacks them and vampirishly drains all blood from their veins, leaving the dead bodies limp and empty."

"What? How?" questioned Larner leaning far forward over the conference table.

The others nodded their heads, and in the eyes of the women there was terror. Larner could not but believe this.

"The beasts, or should I say insects, are as large as your horses and they fly, actually fly, by night, striking down humans, domestic animals and all creatures of warm blood. How many there are we have no means of knowing, and we cannot find their hiding and breeding places. They are not native to our planet, and where they come from we cannot imagine. They are actually monstrous flys, or bugs, or some form of insects."

Larner was overcome by incredulity and showed it. "Insects as big as horses?" he questioned and he could hardly suppress a smile.

"Believe us, in the name of the God of us all," insisted Nern. "They have a mouth which consists of a large suction disk, in the center of which is a lancelike tongue. The lance is forced into the body at any convenient point, and the suction disk drains out the blood. If we only knew their source! They attack young children and the aged, up to five hundred years, alike."

"What! Five hundred years?" exploded Larner again.

"I should have explained," said Nern, simply, "that Venus dwellers, due to our advanced knowledge of sanitation and health conversation, live about 800 years and then die invariably of old age. The only unnatural cause of death encountered is this giant insect. Accidents do occur, but they are rare. There are no deliberate killings on Venus."

Larner did not answer. He only pondered. The more he ran over the strange happenings of the last week in his mind the more he believed he was dreaming. His thoughts took a strange turn: "Why do these vain people go around dressed in jeweled ornaments?"

Nern again anticipated a question. "Diamonds, gold and many of what you call precious stones are common on Venus," he volunteered. "Talc and many other things are more valuable."

"Talc?"

"Yes, we use an immense quantity of it. We have a wood that is harder than your steel. We build machinery with it. We cannot use oil to lubricate these wooden shafts and bearings as it softens the wood, so all parts exposed to friction are sprayed constantly by a gust of talc from a blower.

"You use talc mostly for toilet purposes. We use it for various purposes. There is little left on Venus, and it is more valuable to us than either gold or diamonds. We draw on your planet now for talc. You dump immense quantities. We just shipped one hundred 1,000-ton globes of it from the Cripple Creek district, and the district never missed it. We drew most of it from your mine dumps."

Nern tried not to look bored as he explained more in detail: "We brought 100 hollow spheres constructed of duranium. We suspended these over the Cripple Creek district at an altitude of 10,000 feet above the earth's surface. Because of the crystal glint of duranium they were invisible to earth dwellers at that height. Then we used a suction draft at night, drawing the talc from the earth, filling one drum after another. This is done by tuning in a certain selective attraction that attracts only talc. It draws it right out of your ground in tiny particles and assembles it in the transportation drums as pure talc. On the earth, if noticed at all, it would have been called a dust storm.

"The drums, when loaded with talc, are set to attract the proper planetary force and they go speeding toward Venus at the rate of 426,000 miles an hour. They are prevented from colliding with meteors by an automatic magnetic device. This is controlled by magnetic force alone, and when the targo gets too close to a meteor it changes its course instantly. The passenger targo we ride in acts similarly. And now may I return to the subject of the vampires of Venus?"

"Pardon my ignorance," said Larner, and for the first time in his life he felt very ignorant indeed.

"I know little more than I have told you," said Nern, rather hopelessly. "Our knowledge of your world, your people and your language comes from our listening in on you and observing you without being observed or heard. This might seem like taking an advantage of you, were it not for the fact that we respect confidences, and subjugate all else to science. We have helped you at times, by telepathically suggesting ideas to your thinkers.

"We would have given you all our inventions in this way, gladly, but in many instances we were unable to find minds attuned to accept such advanced ideas. We have had the advantage of you because our planet is so many millions of years older than your own." There was a plaintive note in Nern's voice as he talked.

"But now we are on our knees to you, so to speak. We do not know everything and, desperately, we need the aid of a man of your caliber. In behalf of the distraught people of Venus, I am asking you bluntly to make a great sacrifice. Will you face the dangers of a trip to Venus and use your knowledge to aid us in exterminating these creatures of hell?" There was positive pleading in his voice, and in the eyes of his beautiful sister there were tears.

"But what would my superiors in the Government Bureau think?" feebly protested Larner, "I could not explain...."

"You have no superiors in your line. Our Government needs you at this time more than any earthly government. Your place here is a fixture. You can always return to it, should you live. We are asking you to face a horrible death with us. You can name your own compensation, but I know you are not interested so much in reward.

"Now, honestly, my good professor, there is no advantage to be gained by explanation. Just disappear. In the name of God and in the interests of science and the salvation of a people who are at your mercy, just drop out of sight. Drop out of life on this planet. Come with us. The cause is worthy of the man I believe you to be."

"I will go," said Larner, and his hosts waited for no more. An instant later the targo shot out into interstellar space.

"How do you know what course to follow?" asked Larner after a reasonable time, when he had recovered from his surprise at the sudden take-off.

"We do not need to know. Our machine is tuned to be attracted by the planetary force of Venus alone. We could not go elsewhere. A repulsion ray finds us as we near Venus and protects us against too violent a landing. We will land on Venus like a feather about three months from to-night."

The time of the journey through outer space was of little moment save for one incident. Larner and the other travelers were suddenly and rather rudely jostled about the rapidly flying craft.

Larner lost his breath but not his speech. "What happened?" he inquired.

"We just automatically dodged a meteor," explained Nern.

Most of the time of the trip was spent by Larner in listening to explanations of customs and traditions of the people of the brightest planet in the universe.

There was a question Larner had desired to ask Nern Bela, yet he hesitated to do so. Finally one evening during the journey to Venus, when the travelers had been occupying themselves in a scientific discussion of comparative evolution on the two planets, Larner saw his opportunity.

"Why," he asked rather hesitatingly, "did the people of Venus always remain so small? Why did you not strive more for height? The Japanese, who are the shortest in stature of earth people, always wanted to be tall."

"Without meaning any offense," replied Nern, "I must say that it is characteristic of earth dwellers to want something without knowing any good reason why they want it. It is perfectly all right for you people to be tall, but for us it is not so fitting. You see, Venus is smaller than the earth. Size is comparative. You think we are not tall because you are used to taller people. Comparatively we are tall enough. In proportion to the size of our planet we are exactly the right size. We keep our population at 900,000,000, and that is the perfectly exact number of people who can live comfortably on our planet."

Arriving on Venus, Larner was assigned a laboratory and office in one of the Government buildings. It was a world seemingly made of glass. Quartz, of rose, white and crystal coloring, Larner found, was the commonest country rock of the planet. In many cases it was shot full of splinters of gold which the natives had not taken the trouble to recover. This quartz was of a terrific hardness and was used in building, paving, and public works generally. The effect was bewildering. It was a world of shimmering crystal.

The atmosphere of Venus had long puzzled Larner. While not an astronomer in the largest sense of the word, yet he had a keen interest in the heavens as a giant puzzle picture, and he had given some spare time to the study.

He knew that from all indications Venus had a most unusual atmosphere. He had read that the atmosphere was considerably denser than that of the earth, and that its presence made observation difficult. The actual surface of the planet he knew could hardly be seen due, either to this atmosphere, or seemingly perpetual cloud banks.

He had read that the presence of atmosphere surrounding Venus is indicated to earthly astronomers, during the planet's transit, by rings of light due to the reflection and scattering of collected sunlight by its atmosphere.

Astronomers on earth, he knew, had long been satisfied of the presence of great cloud banks, as rocks and soils could not have such high reflecting power. He knew that like the moon, Venus, when viewed from the earth, presents different phases from the crescent to the full or total stage.

Looking up at the sky from the quartz streets of Venus, Larner beheld, in sweeping grandeur, massed cloud banks, many of them apparently rain clouds.

Nern noted his skyward gaze, and said:

"We have accomplished meteorological control. Those clouds were brought under control when we conquered interplanetary force, and what you call gravity. We form them and move them at will. They are our rain factory. We make rain when and where we will. This insures our crops and makes for health and contentment.

"The air, you will note, is about the same or a little more moist than the earth air at sea level. This is due to the planet's position nearer the sun.

"We have been striving for centuries to make the air a little drier and more rare, but we have not succeeded yet. The heavy content of disintegrated quartz in our soil makes moisture very necessary for our crops, so our moist atmosphere is evidently a provision of providence. We are used to breathing this moist air, and when I first visited the earth I was made uncomfortable by your rarified atmosphere. Now I can adjust myself to breathing the air of either planet. However, I find myself drinking a great deal more water on earth than on Venus."

In this fairyland which had enjoyed centuries of peace, health and accord, stark terror now reigned. In some instances the finely-bred, marvellously intelligent people were in a mental condition bordering on madness.

This was especially true in the farming districts, where whole herds of lats had been wiped out. Lats, Larner gleaned, were a common farm animal similar to the bovine species on earth, only more wooly. On these creatures the Venus dwellers depended for their milk and dairy supplies, and for their warmer clothing, which was made from the skin. The hair was used for brushes, in the building trades, and a thousand ways in manufacturing.

Besides the domestic animals hundreds of people continued to meet death, and only a few of the flying vampires had been hunted down. The giant insects were believed to breed slowly as compared to earth insects, their females producing not more than ten eggs, by estimate, after which death overtook the adult. In spite of this they were reported to be increasing.

In the Government building Larner was placed in touch with all the Government scientists of Venus. His nearest collaborator was one Zorn Zada, most profound scientist of the planet. The two men, with a score of assistants, worked elbow to elbow on the most gigantic scientific mystery in the history of two planets.

A specimen of the dread invader was mounted and studied by the scientists, who were so engrossed in their work that they hardly took time to eat. As for sleep, there was little of it. Days were spent in research and nights in hunting the monsters. This hunting was done by newly recruited soldiers and scientists. The weapons used were a short ray-gun of high destructive power which disintegrated the bodies of the enemies by atomic energy blasts. The quarry was wary, however, and struck at isolated individuals rather than massed fighting lines.

Seated at his work-bench Larner asked Zorn Zada what had become of Nern Bela. In his heart he had a horrible lurking fear that the beautiful Tula Bela might fall before a swarm of the strange vampires, but he did not voice this anxiety.

"Nern and his sister are explorers and navigators," was the reply. "They have been assigned to carry you anywhere on this or any other planet where your work may engage you. They await your orders. They are too valuable as space-navigators to be placed in harm's way."

Breathing a sigh of relief, Larner bent to his labors.

"What other wild animals or harmful insects have you on this planet?" he asked Zorn.

"I get your thought," replied the first scientist of Venus. "You are seeking a natural enemy to this deadly flying menace, are you not?"

"Yes," admitted Larner.

"All insects left on Venus with this one exception are beneficial," said Zorn. "There are no wild animals, and no harmful insects. All animals, insects and birds have been domesticated and are fed by their keepers. We get fabrics from forms of what you call spiders and other web-builders and cocoon spinners. All forms of birds, beasts and crawling and flying things have been brought under the dominion of man. We will have to seek another way out than by finding an enemy parasite."

"Where do you think these insect invaders came from?" asked Larner.

"You have noticed they are unlike anything you have on earth in anatomical construction," said the savant. "They partake of the general features of Coleoptera (beetles), in that they wear a sheath of armor, yet their mouth parts are more on the order of the Diptera (flys). I regard them more as a fly than a beetle, because most Coleoptera are helpful to humanity while practically all, if not all, Diptera are malignant.

"As to their original habitat, I believe they migrated here from some other planet."

"They could not fly through space," said Larner.

"No, that is the mystery of it," agreed Zorn. "How they got here and where they breed are the questions that we have to answer."

Long days passed on Venus. Long days and sleepless nights. The big insects were hunted nightly by men armed with ray-guns, and nightly the blood-sucking monsters took their toll of humanity and animals.

Finally Larner and Zorn determined to capture one of the insects alive, muzzle its lance and suction pad, and give it sufficient freedom to find its way back to its hiding place. By following the shackled monster the scientists hoped to find the breeding grounds.

All the provinces of the planet joined in the drive. Men turned out in automatic vehicles, propelled by energy gathered from the atmosphere. They came on foot and in aircraft. Mobilization was at given points and, leading the van, were Zorn and Larner and their confreres in the targo of Nern and Tula Bela. The great army of Venus carried giant searchlights and was armed with deadly ray-guns.

Headquarters of the vast Army of Offense was in the targo of the Belas. Larner was in supreme command. Just before the big army set out to scour the planet to seek the breeding place of the monsters Larner issued a bulletin that set all Venus by the ears.

Addressed to President Vole Vesta of the Republic of Pana and the good people of Venus, it read:

As is generally known, it has been the habit of the nation's space-flying merchantmen to visit the sunlit side of the planet Mercury to obtain certain rare woods and other materials not found on this planet.

One side of Mercury, as is known, is always turned from the sun and is in a condition of perpetual night. In this perpetual darkness and dampness, where many rivers flow into warm black swamps, the vampires have bred for centuries. Conditions were ideal for their growth, and so through the ages they evolved into the monsters we have encountered lately on Venus.

During some comparatively recent visit to Mercury the grubs of these insects have found their way abroad a vegetation-laden targo left standing near the edge of the black swamps of Mercury. These grubs were thus transported to Venus and underwent their natural metamorphosis here. Reaching adult stage, they have found some place to hide and breed, and thus is explained the origin of the vampires of Venus.