360 bulletin: museum of comparative zoology. 



broader than long, rather flat, ecarinate. Thorax with the pronotum 

 convex behind, the dorsal outline of the mesonotum and base of 

 epinotum continuous and very straight, the base and declivity of the 

 epinotum subequal, forming a sharp angle. Petiolar scale much 

 compressed anteroposteriorly, not quite as high as the epinotal angle, 

 with sharp, entire and rounded superior border. Gaster and legs of 

 the usual shape. 



Only moderately shining, finely shagreened, gaster more sharply 

 and transversely and with a silky luster. Mandibles shining, finely 

 punctate. 



Hairs yellow, short, sparse, erect, absent on the thorax and petiole. 

 Pubescence distinct, but very short and dilute on the cheeks and sides 

 of the head. 



Dull brownish yellow; palpi brown; funiculi, except the basal 

 joint, and anal segment of gaster black; second, third, and fourth 

 gastric segments with a narrow black spot of variable extent near the 

 ventral margin on each side. Small workers with the space between 

 the eyes dark brown. Sometimes this area is reduced to three ocellus- 

 hke spots with vague outlines. 



Described from numerous specimens taken in a piece of dry wood- 

 land near the Baron Falls at Kuranda, Queensland from a single 

 colony evidently hunting for the brood of an I^idom^,Tmex nest which 

 I had excavated in the soil a few hours pre^nously. 0. jocosus is a 

 very distinct form not only in the peculiar shape of the head of the 

 larger worker, the shape of the epinotum and the coloration of the 

 gaster but also in having clearly dimorphic workers. 



16. Opisthopsis linnaei Forel. 



Opisthopsis linnaei Forel, Mitth. Zool. mus. Berlin, 1901, 2, p. 26, S ; 

 Dahl, Leben d. ameis. Bismarck Archip., 1901, p. 42; Viehmeyer, 

 Abh. ber. K. zool. anthr. ethn. mus. Dresden, 1912, 14, p. 23. 



Worker. Length 5.8 mm. 



"Closely related to 0. haddoni, but entirely opaque, including the 

 mandibles and legs; only the head anteriorly and on the sides, shining. 

 The striated and reticulated sculpture is deeper, sharper and micro- 

 scopically uneven. The sides of the rather elongated head are less 

 convex (very feebly convex). Gaster entirely yellow (in haddoni the 

 posterior half is black). In other respects like haddoni but the color 

 is less vivid, more of a dirty, rusty yellow." (Forel). 



