BY ROWLAND E. TURNER. 199 



I do not consider the distinctions given by Guerin for Thynnoides 

 are sufficiently marked when a large number of species are 

 examined. 



Type, Thynnus dentatus Fab. 



Ashmead's subgenera are very misleading; his species taken 

 for the types are often wrongly identified, and the pairing is 

 usually inaccurate. T. pedestris Fab., being the type of Myrme 

 codes Latr., that name must sink, as pedestris is undoubtedly a 

 true Thynnus. 



146. Thynnus dentatus Fab. 



Thynnus dentatus Fab., Syst. Ent. p.360, n.l, 1775(<J); Smith, 

 Cat. Hym. B.M. vii. 11, 1859(<J); Latr., Gen. Crust, et Insect, i. 

 T.13,f.2-4, 1806(<J). 



Smith gives a fair description of the male. Median segment 

 vertically truncate and overlapped by scutellum and postscu- 

 tellum. Abdomen conical, first segment truncate at base and 

 not divided by a groove from the second beneath. Dorsal plate 

 of apical segment longitudinally striated, narrowly emarginate 

 at apex. 



£. Head smooth and shining, strongly rounded at posterior 

 angles, front deeply excavated above base of antennae, the con- 

 cave area, extending two- thirds of the distance to the posterior 

 margin, divided by a broad longitudinal carina, the surface of 

 which is hollowed, longitudinally striated and thinly clothed 

 with long hairs; on each side near base of carina, about half-way 

 to eye, is a cluster of deep punctures from which spring a few 

 long hairs. Eyes oval, not reaching base of mandibles. Pro- 

 notum as wide as head, anterior margin straight, narrowed pos- 

 teriorly and broadly emarginate on posterior margin; covered 

 with large shallow punctures, a row of deeper punctures along 

 anterior margin from each of which springs a hair. Mesonotum 

 small and smooth; median segment short, almost smooth, obliquely 

 truncate posteriorly. First abdominal segment vertically trun- 

 cate anteriorly, the surface of the truncation concave, a trans- 

 verse carina just before the apex of the segment and a cluster of 



