544 Saw-flies, Gall-flies, Ichneumons, 



first described as members of new genera. A flourishing Eciton colony 

 may comprise several thousand individuals. 



Interesting and common Myrmicids are the little Cremastogasters, of 

 which one of the most abundant Eastern species is C. lineolata, the shed- 

 builder ant. It is a small black and yellowish-brown species, the workers 

 measuring from % to T \ inch in length, which usually lives in nests in 

 decaying logs or stumps or in the ground under stones. But sometimes it 

 builds a nest out of chewed wood, like a large rough gall attached to some 

 bush above ground. Atkinson describes such a nest (Fig. 748) 18 inches long 

 and 12 inches in circumference which contained adults, larvae, and pupae. 

 In addition to these nest-sheds, small temporary sheds are sometimes built 

 at some distance from the nest "over the herds of Aphids, or scale-insects, 

 from which they obtain honey-dew." 



Another interesting and abundant Myrmicid is the minute yellow "thief- 

 ant, " Solenopsis molesta. Although it sometimes lives in independent nests, 

 more often by far it is to be found living in association with some larger ant 

 species it consorts with many different hosts feeding almost exclusively 

 on the live larvae and pupae of the host. The thief-ant is so small and obscurely 

 colored that it seems to live in the nest of its host practically unperceived. 

 The Solenopsis nest may be found by the side of the host-nest, around it, 

 or partly in it, the tiny Solenopsis galleries ramifying through the nest-mass 

 of the host, and often opening boldly into these larger galleries. Through 

 their narrower passages, too narrow to be traversed by the hosts, the tiny 

 thief-ants thread their way through the other nest in their burglarious excur- 

 sions. 



As an example of Myrmicids which live in compound or mixed nests the 

 species Myrmica brevinodes, a common red-brown ant that lives under stones 

 in the East, and the smaller Leptothorax emersoni may be referred to. 

 The interesting symbiotic life of these ants has been studied and carefully 

 described by Wheeler (American Naturalist, June, 1901). The little Lep- 

 tothorax ants live in the Myrmica nests, building one or more chambers with 

 entrances from the Myrmica galleries, so narrow that the larger Myrmicas 

 cannot get through them. When needing food the Leptothorax workers 

 come into the Myrmica galleries and chambers and, climbing on to the backs 

 of the Myrmica workers, proceed to lick the face and the back of the head 

 of each host. A Myrmica thus treated "paused," says Wheeler, "as 

 if spellbound by this shampooing and occasionally folded its antennae as if in 

 sensuous enjoyment. The Leptothorax, after licking the Myrmica's pate, 

 moved its head around 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 



