8 WHEELER. [VOL. II. 



because they are the only known egg-laying individuals of the 

 species. The winged, light-yellow male of L. clongata was de- 

 termined on circumstantial evidence, as it could not be found 

 in the natural nests, nor bred from the cocoons in the arti- 

 ficial nests. What seemed to be the males (Fig. 4, $) were 

 found during the autumn and spring flying about the lights in 

 the houses. They are somewhat smaller than the workers, have 

 very large eyes and ocelli, and the node is shaped like that 

 of the female. When placed in the artificial nests of L. clon- 

 gata they are not only not molested, but move about among 

 the workers as if they had always belonged among them. To 

 one who has witnessed the hostility of these ants to any ant of 

 a different species placed in their nest, this amicable reception 

 amounts to a demonstration of specific identity. 



During the course of my observations I have had frequent 

 opportunity to observe the conduct of all three species of 

 Ponerinae towards ants of the same or of different species 

 introduced into their nests. They are always hostile to ants 

 of a different species, but the aggressive nature of this hostility 

 varies according to circumstances. If one or a few strange ants 

 be placed in a nest of Ponerinae, they will be at once attacked 

 and killed by concerted action, but if a single Ponerine be 

 placed in the nest of another species --say in a nest of the 

 agricultural ant (Pogonomyrmex barbatus) - - it will if attacked 

 defend itself valiantly with its mandibles and sting, but it will 

 prefer to seek refuge in some corner of the nest and remain 

 concealed. Single specimens of P. harpa.v, introduced at dif- 

 ferent times into the nest of P. barbatus, managed to evade the 

 pugnacious agricultural and to remain alive for days. When- 

 ever they left their concealment, however, they would be at- 

 tacked by a swarm of agricultural, but the Ponerinae were 

 so supple and fierce that they always managed to throw off 

 their assailants and to conceal themselves. Other investiga- 

 tors, like Forel and Wasmann, have called attention to this 

 difference in the pugnacity of ants according to whether they 

 find themselves alone or backed by numbers of their own species. 



The species of Ponerinae differ in their reception of ants of 

 the same species from other nests. If two nests of workers 



