Another implacable foe of these creatures is the larva of a neuropterous insect which in its perfect or mature form resembles the dragon fly. It is technically known as an aphis-lion, and differs very widely in habits from the common and well-known ant-lions. The last-mentioned grubs dig pits, at the bottoms of which they lie in wait for and seize their prey whenever it falls therein; the aphidian lion is, on the contrary, a bold and skillful hunter, and takes its prey wherever it may find it. It is an ugly, heavy, slothful-looking grub, yet it is remarkably agile. When darting upon its quarry (and it hunts the winged aphides only), its thick, clumsy-looking legs move with such rapidity that they can scarcely be seen. Its movements as well as its shape are decidedly lacertilian; in fact, when it is seen coursing over the grape leaves in pursuit of its prey, it reminds one irresistibly of the brilliant little lizards which are to be observed running here and there over stone walls, fences, and sunny woodland paths. This creature stalks its prey like the lycosids or hunting spiders, and fairly bounds upon it when it arrives within grasping distance. Its catlike movements when creeping up on its quarry are wonderful to behold, and indicate a very high degree of intelligence.
A Colony of Aphides.
In color it is jet black; in fact, in certain lights it glistens like a jet jewel. It is about half an inch long and one sixteenth of an inch broad. On the margins of its body, from its head to its tail, are rows of thorn-like spines. Its masticatory organs, as well as its viscera, are much more highly developed than are those of ant-lions. It is a brave little creature, and only succumbs to the ants (which make war on it wherever they find it, thus showing that they are fully aware of the fact that it is inimical to their herds) when life ceases. During the last twenty years I have frequently observed this larva, and have endeavored to follow it in its metamorphoses. I have succeeded only once, however, in carrying it through to its imago or perfect form. It is not described in any of my lists, and may be, therefore, a new species. There is another aphis-lion which in very many respects closely resembles the one just described. It is pictured by Professor Comstock, a modification of whose drawing is here produced. He writes of this creature as follows:
"When the aphis-lion is full grown, it rolls itself up into a tiny ball and weaves around itself a glistening, white cocoon, which looks like a seed pearl." (This can be seen in the sketch near the base of the upper leaf.) "It may be supposed that while the aphis-lion is secluded in this pearly cell it repents its greedy, murderous ways, and changes in spirit; at least the body changes greatly, for, after a time, a circular lid is made in the cocoon, and out of it there emerges a beautiful, dainty creature, with delicate-veined, green wings, a pale-green body, slender brown antennæ, and a pair of large eyes that shine like melted gold. It is sometimes called golden-eyes, and sometimes a laced-wing fly, from its appearance."
This beautiful little insect evinces marvelous forethought in the matter of perpetuating her kind. She knows that her young are predaceous, devouring anything in the shape of an insect or an egg that they can secure; she is aware of the fact that, if she were to deposit her eggs, side by side, on a leaf, the first young aphis-lion hatched out would devour all of the remaining eggs. In order to guard against this, she spins a delicate but stiff stalk of hard silk, upon the tip of which she deposits an egg. By the side of this stalk she rears another, and another, and another, tipping each with an egg, until finally, when she has finished ovipositing, there appears a miniature grove of delicate silken stems, each one of which bears aloft on its summit a round and shining egg. When the first-born of this brood makes its appearance, it crawls down the stem to the surface of the leaf, and goes in search of food, utterly unconscious of the rich and toothsome feast just above its head on the tips of the other stalks!
Lubbock concludes, from certain experiments, that the yellow ant will not voluntarily drop from an elevation. Now, observations and experiments made by myself teach me that these ants (Lasius flavus) will drop from elevations when they wish to attain a certain object.
On one occasion one of the herds of aphides under observation was discovered by a wandering black ant (Lasius niger), which reported her discovery to her comrades. At once a marauding expedition was inaugurated by these cattle thieves, which fiercely attacked the yellow guardians of the herd. The black rievers swarmed up the grapevine, but were met by the brave yellow warriors, which valiantly withstood their attack. Finally, the yellow ants were in danger of being overwhelmed by numbers, when I suddenly perceived that they were being re-enforced. Closer examination revealed the fact that they were crawling up a neighboring vine and then dropping from an overhanging leaf on to the leaf on the stem of which the aphides were feeding. They could not reach the herd by way of the original path on account of the intervening army of black ants, hence their shrewd and most intelligent use of the neighboring vine and overhanging leaf. I am glad to report that the yellow ants were victorious, and that they completely routed the would-be robbers.
When alarmed, the yellow ant will draw in its legs and drop to the ground; moreover, this is characteristic of all vine- and tree-climbing ants, Lubbock to the contrary notwithstanding. It stands to reason that past experiences must have taught them that they received no injury from involuntary tumbles; that they have evolved the habit of voluntarily throwing themselves from an elevation in order to attain certain objects does not seem to me, therefore, at all wonderful or extraordinary.