wheeler: ants of the genus opisthopsis. 343 



The interesting resemblance of these ants to the large-eyed, arboreal 

 and bright-colored species of Pseudomyrma in the Neotropical and of 

 Sima in the Palaeotropical region led me to look for their nests in the 

 trees, but I failed in this quest and concluded that the nests must be 

 at inaccessible heights in the trunks or branches. Through a fortu- 

 nate accident, however, at Koah, near Kuranda, Queensland, I dis- 

 covered the nests of one species, 0. haddoni. In this arid forest region 

 there are innumerable termite nests of all sizes from a foot or two to 

 six or seven feet in height. I found that the smaller nests could be 

 easily broken off at the base and turned over by a sharp kick ^ath the 

 foot. This exposed the galleries in the base of the termitarium and to 

 my surprise I found them in nearly every nest inhabited by a colony 

 of the beautiful orange and black haddoni. Such stud}' as I could 

 make in the field showed that the ants take possession of the galleries 

 by replacing the termites, which retreat to the upper portion of the 

 nest-cone. Perhaps the ants feed verj- largely on the soft-bodied 

 termites, although the latter were not molested when they happened 

 to creep into galleries inhabited by the ants. From this and the 

 further fact that I found haddoni nesting by itself under stones only 

 on one occasion, I infer that this ant is regularly termitophilous. 

 Later I again found haddoni nesting in precisely the same manner in 

 termitaria near Towns\'ille, Queensland. 



On my return to the United States I learned that Dr. E. Mjoberg 

 (in Forel, Ark. f. zool., 1915, 9, p. 95) had recently made similar 

 observations on 0. haddoni in the Kimberley District of North West 

 Australia and at Laura, Cape York and Colosseum, Queensland. He 

 also succeeded in finding the nests of 0. rufithorax " in clay about the 

 roots of trees." Nevertheless this terrestrial method of nesting is by 

 no means universal in the genus. Dahl discovered the nests of 0. 

 linnoei in tree-trunks in the Bismarck Archipelago, and Mann recently 

 found a nest of 0. vianni in a similar situation in the Solomon Islands. 

 In all probability 0. respiciens will be found to have similar habits. 



The colonies of 0. haddoni are rather small, comprising only about 

 100 to 200 workers "wnth a single or several dealated queens. The 

 larvae are white and plump and covered T\ath short, simple hairs. 

 They spin pale buff-colored cocoons like most Camponotinae. It is 

 easy to capture the ants in their nest as they seem to be dazed when 

 the termitarium is suddenly broken in two and the light let into their 

 galleries. In this connection I may state that numerous other ants 

 are quite as regularly found nesting in termitaria at Koah and Towns- 

 ville, Queensland. In both localities the very pugnacious Iridoviyr- 



