352 THE WONDER OF LIFE 



to secrete a sort of honey dew. It looks as if the pupa 

 served as a food purveyor to the ants, but it would be satis- 

 factory to have some observational verification of this. It 

 would also be interesting to know whether the pupa gets 

 any quid pro quo, whether the winged insect when it emerges 

 is not possibly in need of some assistance from the ants. 



F. Le Cerf describes a remarkable association between 

 a Lycaenid caterpillar and a colony of ants of the genus 

 Cremastogaster. The case was discovered by MM. 

 Alluaud and Jeannel on the Kikuyu escarpment. Certain 

 acacias bear numerous nut-like galls, perforated by an 

 orifice about 1 mm. in diameter through which the ants 

 go out and in. The caterpillar is about 10 mm. in length, 

 curiously like a wood-louse or a Chiton, and bearing very 

 peculiar modified hairs. Its mouth-parts suggest a 

 vegetarian diet, and it probably feeds on the acacia leaves 

 which the ants store. It could not possibly get out of the 

 gall, and it must have been reared there by the ants. 



GUESTS AND PETS 



A great number of cases are now known where small 

 beetles or other insects live in terms of friendly association 

 with ants. One of the most extraordinary cases is that of 

 the cricket genus Myrmecophila, some species of which have 

 become guests of ants. Particular guests are wont to be 

 associated with particular hosts ; thus Myrmecophila acer- 

 vorum is usually found in the nests of the black ant, Lasius 

 niger, and, in suitable localities, of the red ant, Myrmica 

 rubra. The reason for the picking and choosing of a host 

 is probably to be found in some adaptation in the relative 

 size of host and guest. The little crickets get shelter 

 and food ; they lick their hosts, who give up some 



