342 bulletin: museum of comparative zoology. 



the color differences are constant within certain easily discernible 

 limits, I follow the example of Emery and Forel and recognize eleven 

 species. Two of these, pidus Emery and rufithorax Emery, should 

 probably be united, as the former is unusually variable in color and 

 has one variety that is transitional to rufithorax. I may add that 

 although I have examined more specimens of Opisthopsis than any 

 pre\'ious worker, the final decision as to the limits of the species, 

 subspecies, and varieties must be left to the resident Australian 

 entomologist who can make an intensive study of the geographical 

 distribution of the group. My account of these insects will, I trust, 

 show that both their habits and taxonomy merit closer investigation. 



The genus Opisthopsis is evidently very largely confined to xVustralia, 

 as only one species {0. linnaei) is known from the Bismarck Archi- 

 pelago, one {0. respiciens) from New Guinea and one (0. vumni) from 

 the Solomon Islands. Opisthopsis respiciens, moreover, is common 

 also in Northern Australia and 0. haddoni may occur in New Guinea. 

 The precise ranges of the various Australian species cannot be given 

 at the present time. Forel's statement that 0. respicie7is is " in ganz 

 Australien verbreitet," is, I am sure, erroneous. I failed to find any 

 Opisthopsis in Eastern Australia south of Brisbane, Queensland 

 (27° 30' S.), and with the exception of some specimens of 0. rufithorax, 

 I have seen none taken in a more southern latitude. Froggatt does 

 indeed record 0. respiciens from New South Wales and Mayr cites 

 it from Sydney, but Froggatt's specimens may have been collected 

 near the Queensland border and Mayr's may have been specimens of 

 rufithorax. All the species I have seen in the field were living at low 

 elevations in the dense "scrub" (tropical rain forest) or dry, open 

 "forest" of Queensland. Opisthopsis respiciens seems to prefer the 

 former, tlie paler, yellow species (haddoni, major, jocosus, rufithorax, 

 etc.) the latter situations. 



The workers are usually seen running in the bright sun-light up and 

 down the trunks of large trees, especially of the genera Eucalyptus and 

 Melaleuca, with rapid, jerky movements like those of our large-eyed, 

 neotropical Pseudomyrmas. They have extremely acute ^^sion, as 

 would be inferred from the large size, very fine facetting and peculiar 

 position of the eyes, and are therefore very difficult to catch, as they 

 look backward as well as sidewise and forward and dodge about with 

 such adroit zigzag movements that it is almost impossible to seize 

 them with the tweezers or fingers. I finally resorted with greater 

 success to slapping them with the hand, but this is apt to crush them 

 or to make them fall from perpendicular surfaces. 



