426 THE ANIMALS AND MAN 



nests, building one or more chambers with entrances from 

 the Myrmica galleries, so narrow that the large Myrmicas 

 cannot get through them. When needing food the Lepto- 

 thorax workers come into the Myrmica galleries and chambers 

 and, climbing on the backs of the Myrmica workers, proceed 

 to lick the face and the back of the head of each host. A 

 Myrmica thus treated, says Wheeler, "paused, as if spell- 

 bound by this shampooing and occasionally folded its 

 antennae as if in sensuous enjoyment. The Leptothorax 

 after licking the Myrmiccfs pate, moved its head round to 

 the side and began to lick the cheeks, mandibles, and labium 

 of the Myrmica. Such ardent osculation was not bestowed 

 in vain, for a minute drop of liquid evidently some of the 

 recently imbibed sugar-water appeared on the Myrmica's 

 lower lip and was promptly lapped up by the Leptothorax. 

 The latter then dismounted, ran to another Myrmica, 

 climbed on its back, and repeated the very same performance. 

 Again it took toll and passed on to still another Myrmica. 

 On looking about in the nest I observed that nearly all the 

 Leptothorax workers were similarly employed." 



Wheeler believes that the Leptothorax get food only in 

 this way. They feed their queen and larvae by regurgita- 

 tions. The Myrmicas seem not to resent at all the presence 

 of their Leptothorax guests, and indeed may derive some 

 benefit from the constant cleansing licking of their bodies by 

 the shampooers. But the Leptothorax workers are careful to 

 keep their queen and young in a separate chamber, not 

 accessible to their hosts. This is probably the part of 

 wisdom, as the thoughtless habit of eating any conveniently 

 accessible pupae of another species is wide-spread among 

 ants. 



Social and communal life.- -The simplest form of true 

 social life exists among those animals in which many in- 

 dividuals of one species keep together, forming a great band 

 or herd. Such animals are said to be gregarious in habit, 



