194 REVISION OP THE THYNNID^E OP AUSTRALIA, II., 



Subgenus Macrothynnus, n.subgen. 



$. Labrum broad and full as in Thynnus, from which it may 

 be distinguished by the antennae which are slender at the apex. 



9- Pygidium truncate posteriorly and broadly oval, not con- 

 tracted before or on the truncation. 



This group consists of a few very large species, two of which, 

 T. friederici D.T., and T. poultoni, may have to be separated 

 when closer examination is possible. 



Type, Thynnus simillimus Sm. 



141. T. (Macrothynnus) simillimus Sm. 



Thynnus simillimus Sm., Cat.Hym.B.M.vii.p.l5,n.l2,1859( ( J). 

 Thynnus molitor Sm., I.e. p.43, n.120, 1859(9). 



(J. Clypeus broad, truncate at apex, rugose. Head, thorax and 

 median segment rugulose; median segment short, truncate from 

 a little behind postscutellum, rounded at sides and covered with 

 grey pubescence. Abdomen very closely covered with minute 

 punctures, first segment as broad as second. Hypopygium with 

 slight prominences at basal angles, very broad and rounded to 

 apex, with a very short apical spine. Wings fusco-hyaline, with 

 a purple sheen. 



9. Head coarsely and rather sparsely punctured, not quite as 

 broad as pronotum. Thorax and abdomen sparsely and finely 

 punctured, the four apical abdominal segments smooth at base. 

 First abdominal segment with the apical margin raised and 

 several transverse striae before it. Second segment crossed near 

 middle by eight transverse carinse between two rather more 

 elevated transverse carina?, the apical margin raised, with four 

 very small transverse carinas just before it, and seven or eight 

 very fine transverse carinse near base, the whole forming a con- 

 tinuous series. Fifth ventral segment coarsely longitudinally 

 striated, smooth at base. Pygidium smooth at base, not much 

 contracted, vertically truncate posteriorly, with many arched 

 carinse on the surface of the truncation, which is large and oval; 

 epipygium reflexed at apex. 



