AMERICAN IIYMENOPTERA. 



291 



versely, and surrounded by a projecting border around whicb the 

 granulations which cover the whole body of the larva are especially 

 massed. Out of this sort of button-hole, and at the middle, rises, at 

 the will of the grub, a species of hemispherical, transparent vescicle, 

 which gives passage to a serous liquid sufficiently abundant to form a 

 large drop, which is reproduced whenever it is removed. The larva 

 does not secrete this liquid except when disturbed imitating in this 

 the Cuinllia and many other larvtc which disgorge at the mouth a 

 colored liquid, with the intention, doubtless, of repelling those who 

 molest them. M. Guonee ventures no opinion as to the economy of 

 this exceptional structure. But, his description throws great light 

 upon the behaviour of the ants as recorded above. There can be 

 little doubt that the gathering of a serous liquid, like that observed 

 by M. Guenee, upon Lt/cfT.na bafica, was the object of the attend- 

 ance of the ants of Formica suhserked upon the Lyca3nid larva as 

 observed by myself. This larva (in alcohol), was placed in Dr. Leidy's 

 hands for examination, under the microscope. He found on each side 

 of the two (or three) last segments, on the dorsal sur- 

 i'ace, a prominent, circular, brown-colored glandular 

 looking boJy, with a central depression. These glands 

 were quite distinct from the spiracles, which are not 

 represented in the accompanying cut. Fig. 11 shows 

 the appearance of these glands as situated upon one 

 side of the terminal segments. It is possible that 

 the last three segments are here represented, the last 



" ■ ' ''"'^ "! (twelfth) being contracted. Dr. Leidy found no open- 

 unon terminal ; , • n , 



seeinents of L\'- '"n ^^ ^iie summit of the tenth or otlier segment, 



ciBiiid larva, at- corresponding with the button-hole like secretory gland 



tended by For- described by M. Guen6e. The above facts are all of 



mica subfiericea. i. • ^ ,. i i. i. ,.1 • 



very great interest, and may prove to be another im- 

 portant factor in solving questions concerning the food supply of ants 

 under br)th ordinary and extraordinary circumstances. 



Natural Kiieiuies.— When we consider the viist numbers of insects 

 witliiii a single commiiiiity of the fallow ant, and their apparent ini- 

 uiuiiity from the destructive effects of climate, we are not only deepl}' 

 interesteil but much pjr|)lexed under the inquiry, what are the agents 

 and influences tliat liniit their increase;* II' tiie amicable relations 

 existing under my own observations are permanent, their numbers are 

 not held in check by civil wars. There appears to be an established 

 feud between them and the large black Carpenter Ant, Camjjouotus 



