142 FURTHER ILLUSTRATIONS OF 
very short clypeus, and the broad but entire mandibles, of which 
the tips are black, and the under-side furnished with long hairs 
(fig. 3a); the labrum is short, exposed and setose; the maxillary 
palpi are very small, but they consist of six joints (fig. 36, 3c) ; 
the labial palpi are also minute, but they are four-jointed (fig. 3 d, 
3e); the prothorax is large and quadrate, bemg broader than 
the head, with the posterior portion rather narrowed; it is finely 
punctured and has a circular impression on each side, which may, 
however, possibly be accidental; the mesothorax is small and 
chesnut-red, and the metathorax black and punctated, with the 
lateral angles rounded off. The abdomen is very large, and semi- 
cylindrical, the first and second segments being destitute of gloss 
and very finely rugose, and the remaining segments glossy and 
impunctate; the anterior segment is yellow above, with several 
black dots on the deflexed basal part, and the hind margin is also 
black; the second segment has the anterior and posterior margin 
black, and of equal breadth ; the following joints are also similarly 
coloured, but the black basal part is much broader than the 
posterior margin; the sides of the intermediate segments are 
also dotted with black; the fifth segment is nearly as large as the 
preceding and not emarginate at its hinder edge; the terminal 
segment is entirely black, thick, convex above, truncated at the 
extremity, with the sides slightly striated (3, 3g). The abdomen 
beneath is pitchy, varied with obscure red, the fourth segment 
having two transverse marks of this colour; the first segment is 
angulated at its base. The legs are chesnut-red; the anterior 
short, with the spur at the extremity of the tibiz half as long as 
the tarsi; the basal joint of the tarsi, on the outer edge, spinose ; 
the posterior femora are emarginate on the hinder edge, beyond 
the middle, and the posterior tarsi are twice as long as the 
tibiee. 
The six-jointed maxillary and four-jointed labial palpi, together 
with the strong spur of the fore-feet, the character of the second 
segment of the abdomen, and the notched posterior femora, 
are characters which do not occur in the females of the typical 
Thynni. I cannot, however, regard them as of higher value 
than specific, considering that the true character of the females 
of the genus Thynnus consists in the rudimental size of the palpi, 
and which is not overbalanced by their possessing the typical 
number of joints, 
