552 TRANS. ST. LOUIS ACAD. SCIENCE. 



none in the deeper-necked, narrower, more compact egg-pods 

 either of Caloptenus femur-rubrum^ C. Atlantis^ or CEdipoda 

 sulphurea., in which the eggs are regularly and quadrilinearly 

 arranged as in those of C. spretus. Not only have I found a large 

 proportion of the egg-pods of C. differentialis naturally infested 

 with these Epicauta larvae, but I have succeeded in hatching 

 and rearing numbers in-doors, and have them even at this writing 

 (Oct. 30th) by hundreds in all stages from the first larva to the 

 pseudo-pupa. Referring the reader to the end of this paper for 

 detailed descriptions, let me illustrate the larval habits of the 

 genus by reciting those of one of the species in question, viz., 

 vittata. 



From July till the middle of October the eggs are being laid in 

 the ground in loose, irregular masses of about 130 on an average 

 — the female excavating a hole for the purpose, and afterwards 

 covering up the mass by scratching with her feet. In confine- 

 ment she sometimes omits both these instinctive acts and ovi- 

 posits on the surface of the ground. She lays at several difterent 

 intervals, producing in the aggregate probably from four to five 

 hundred ova, judging from examinations made on the ovaries of 

 some that were gravid. She prefers for purposes of oviposition 

 the very same warm sunny locations chosen by the locusts, and 

 doubtless instinctively places her eggs near those of these last, as I 

 have on several occasions found them in close proximity. In the 

 course of about 10 days — more or less, according to the tempera- 

 ture of the ground — the first larva ortriungulin hatches. The hatch- 

 ing takes place without the aid of any ruptor ovi, for the egg-shell 

 is so delicate that it easily splits, from mere expansion, along the 

 back near the head, and breaks and shrivels up with the escape 

 of the larva. These little triungulins (PI. V., Fig. 2), at first fee- 

 ble and perfectly white, soon assume their natural light brown 

 color and commence to move about. At night or during cold or 

 wet weather all those of a batch huddle together with little mo- 

 tion, but "when warmed by the sun they become very active, run- 

 ning with their long legs over the ground, and prying with their 

 large heads and strong jaws into every crease and crevice in the 

 soil, into which, in due time, they burrow and hide. Under the 

 microscope they are seen to fairly bristle with spinous hairs, which 

 aid in burrowing. As becomes a carnivorous creature whose 



