A DECADE OF AUSTRALTAN THYNNIDEOUS INSECTS. 121 
unique specimen. The mandibles are black on the inside and 
yellow on the outside, the tips and inner margin being, however, 
black ; the maxillee have a long row of slender hairs on the outside, 
and the palpi are rather elongated. The thorax is black, the wing- 
scales and a very slender transverse line behind the scutellum being 
dirty white ; the abdomen is black, depressed, narrower than the 
thorax, its broadest part being in the middle; the five anterior 
segments marked on each side, at the posterior margin, with a 
very slender dirty white lunule; the basal segment has a deep 
longitudinal channel down the middle; the body beneath is black, 
with slight gray pubescence, the intermediate segments of the 
abdomen with extremely slender white lunules behind; the apical 
segment is entire and rounded. The anterior feet are castaneous, 
with the tips of the tarsi black; the middle feet are castaneous 
before, but black behind, and the hind feet are entirely black. 
The wings are slightly tinged with grayish, and the stigma is 
black. Inhabits King George’s Sound. In Mus. Westw. 
THYNNUS DIMIDIATUS, Westw. 
(Plate 76. fig. 5.) 
T. niger punctatus abdomine (segmento basali excepto) tibiis tarsisque ferrugineis, ano 
5-dentato. ¢ 
Long. corp. lin. 6. Expans. alar, lin. 93. 
This curious species has the head and thorax entirely black, 
finely punctured, and clothed with slight gray pubescence ; the 
clypeus is porrected between the mandibles, which are dark 
castaneous, with the tips black. The antenne are rather short 
(about two lines long), and black ; the trophi are black ; the outside 
of the maxillz clothed with long whitish hairs; the dise of the 
mesothorax is scarcely marked by the four impressed lines, and 
the metathorax is far more delicately punctured than the scutellum. 
The dorsal segment of the abdomen is black ; the remainder dark- 
brick red. The segments are much constricted at the articulations, 
where in each is a transverse impressed line running across the 
joint, finely serrated; the penultimate segment is armed at each 
side with a short ferruginous spine, and the terminal segment with 
a deflexed acute black point, the base of which, on each side, is 
armed with a shorter black diverging curved spine; the legs are 
black, with the tips of the femora and the tibiz and tarsi dark 
ferruginous. The wings are rather tinged with gray, and the 
stigma is black. 
