120 Mr. R. E. Turner on Fossorial Hymenoptera. 



a more slender species, the first abdominal segment is much 

 narrower and proportionately longer, the scutellum is rather 

 less convex, the third abscissa of the radius is much longer, 

 and the second recurrent nervure is received further from 

 base o£ the third cubital cell. 



Dimorpliotliynnus hicolor, Westw. 



Enteles hiculor, Westw. Arc. Ent. ii. p. 143 (1844). $ . 

 Thynnus zingerlei, D. T., Cat. Hym. viii. p. 119 (1897). $. 

 ^ Rha (jig aster hmnorrhoidalis, Guer. Mag. de Zool. xii. (1842). c?. 

 ? Thynnus lecheri, D. T., Cat. Hym. viii. p. 110 (1897). 6- 

 Enteles hcemorrhoidalis, Turn. Proc. Linn, Soc. N.S.W. xxxii. p. 242 

 (1907). $. 



I used the name hcemorrJwidalis for this species in my 

 revision of the group, probably correctly. But since that 

 time I have received the male of Rliagigaster castaneus, Sm., 

 whicli would fit Guerin's very brief description equally well. 

 There can therefore be no certainty as to Guerin's species 

 wnthout seeing the type. B. Jimhriatus, Sm._, c? , is a dis- 

 tinctly larger species. 



The pair of D. hicolor in the British Museum is from 

 Perth, W.A. There is a series of D. fimbriatus from 

 Adelaide, S.A., and Yallingup, W.A. 



Dimorphothynnus Jimhriatus, Sm. 



Thynnus fimbriatus, Sm. Cat. Hym. B.M. vii. p. 42 (1869). $ . 

 Rliagigaster apicalis, Sm. Cat. Hym. B.M. vii. p. 63 (1859). S ■ 

 Thynnus ottonis, D. T., Cat. Hym. viii. p. 112 (1897). cT. 



In my revision of the Thynnidas (Proc. Linn. Soc. N.S.W. 

 xxxii. p. 242, 1907) I treated this species as a synonym 

 of D. hcemorrhoidalis, Guer. Further material has come to 

 hand since and shows that I was mistaken. The female 

 fimbriatus differs from hicolor, Westw., in the shape of the 

 head, which is shorter and much more strongly rounded 

 posteriorly, the pronotum and scutellum are shorter ; the 

 median segment is very short, only half as long as in 

 hicolor ; the carinse on the second doi'sal segment are some- 

 what stronger ; the pygidium is much narrower, being 

 very broadly oval in hicolor, elongate and narrowed to the 

 apex in fimbriatus, the striation of the pygidium is much 

 coarser, and there is a tuft of long pale hairs on each side, 

 springing from beneath the dorsaJ plate of the pygidium, 

 which is absent in hicolor. The male hicolor has the enclosed 

 triangular space on the clypeus narrower than in fimbriatus; 

 the seventh dorsal segment more rounded at the apical angles, 



