wheeler: ants of the genus opisthopsis. 347 



12. Gaster entirely or almost entirely yellow 15 



Gaster black at least behind the second segment 13 



13. Head entirely yellow haddoni Emery. 



Vertex and occiput black 14 



14. Second gastric segment yellow only at the base. 



diadematus, sp. nov. 

 Second gastric segment entirely yellow. 



diadematus var. duhius, var. nov. 



15. Third and fourth gastric segments with black markings on the 



sides; workers dimorphic, minor worker with infuscated 



vertex and occiput jocosus, sp. nov. 



Gaster entirely yellow or with only the anal segment blackened; 

 workers monomorphic, head of small workers not infuscated 

 behind 16 



16. Body shining, very indistinctly shagreened. Length 3-4.5 mm. 



manni, sp. nov. 

 Body opaque, sharply shagreened. Length 5.8 mm. 



linnaei Forel. 



1. Opisthopsis respiciens (F. Smith). 

 Plate 1, fig. 1, 2. 



Formica (Myrmecopsis) respiciens F. Smith, Journ. Linn. soc. Zool., 



1864, 8, p. 68, ^ , pi. 4, fig. 3, 3a. 

 Myrmecopsis respiciens Mayr, Journ. Mus. Godeffroy, 1876, 12, p. 76, 



Opisthopsis (Myrmecopsis) respiciens Forel, Ann. Soc. ent. Belg., 1893, 

 37, p. 461, g 9 . 



Opisthopsis respiciens Emery, in Dalla Torre, Cat. Hymen., 1893, 7, 

 p. 219, y ; Emery, Ann. Soc. ent. Belg., 1895, 39, p. 353; Emery, 

 Mem. R. accad. sci., ist. Bologna, 1896, ser. 5, 5, p. 776; Froggatt, 

 Agric. gaz. N. S. W., 1905, p. 28, S ; Forel, Ergeb. Hamb. S. W. 

 Austr. Forschungsreise, 1907, 1, p. 229, S ; Viehmeyer, Abh. 

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



Worker. Length 3-4.5 mm. 



Head evenly convex dorsally and ventrally, with straight posterior 

 margin and evenly convex sides, which converge anteriorly in the region 

 of the cheeks. Eyes large and prominent, rather close together. 

 Mandibles 5-toothed, with convex external borders. Clypeus dis- 



