One of these flies, which can be seen in the drawing, is quite large; I am inclined to believe, therefore, that their larvæ do not pupate in the bodies of their hosts, but undergo further metamorphoses elsewhere. Another of these flies is very small, hardly larger, in fact, than the insect which it selects as a living cradle for its young. The ichneumon shows rare intelligence, inasmuch as she invariably deposits her eggs on the young members--the calves, as it were--of the herd; she seems to know that the older aphides would die before the ichneumon grubs arrived at a suitable age for pupation; hence she selects the young ones. She runs here and there about the colony until she finds a young aphis; then, curving her abdomen between her legs, she will quickly lay an egg on the body of the unconscious insect. When the egg hatches the larva feeds on the body of its host (carefully avoiding the vital organs, however) until the time arrives for it to undergo further metamorphoses. The animated cradle and cupboard eventually dies, but not until its queer baby has arrived at an age at which it has no further use for it. The ants are fully aware of the fact that the ichneumon is a deadly enemy of their cows; hence, when one of these flies is seen hovering over the herd, they at once become alert and endeavor to chase her away whenever she alights. She manages, however, to elude them every now and then, and to lodge her fatal eggs on some of the tender young aphides. 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. [Illustration: A COLONY OF APHIDES.]