88 Mr. J. O. Westwood's Descriptions 



spot on each side ; the third joint is slightly constricted at the 

 base ; it is marked, as well as the fourth joint, with a yellow spot 

 on each side, diminishing in size ; the three following joints are 

 black, glossy, and cylindric, and the last joint is ob-conical, ter- 

 minated by an appendage, which is shortly spinose on each side. 

 The legs are fidvous ; the hind femora clavate, and finely spined. 

 The wings are fulvescent, with dark fidvous veins. The arrange- 

 ment of the veins offer several peculiarities, which exist also in 

 the following species, but not in other insects of the genus. The 

 body beneath is black ; the second abdominal ventral segment 

 with a fulvous fascia, and the third with two fulvous spots. 



Fig. 1. The insect slightly magnified; 1 a, the head and base of the an- 

 tenna seen sideways ; 1 b, the proboscis and its palpi more highly 

 magnified. 



Mydas bispinifer, Westw. (Plate XTII. fig. 2.) 



Mydas niger, thoracis lateribus cum scutello rufo-fulvis ; ab- 

 domine maris elongato angusto clavato, articulis basalibus 

 utrinque flavo-maculatis ; alis versus costam fusco-tinctis, 

 venis nigris ; pedibus pallide flavis ; femoribus posticis cla- 

 vatis. $ 2 



Expansio alarum 10 — 13 lin. 



Habitat in Australia occidentali. 



In Mus. Ince et Saunders. 



The male of this species has somewhat the appearance of a 

 large elongated Conops. It agrees with the preceding species in 

 the peculiar arrangement of the veins of the wings, and in the 

 radiated appendage at the extremity of the body of the female. 

 The head is black, clothed in front with slight grey pubescence, 

 the nasus rather produced and obliquely truncate. The mouth 

 of one of the specimens examined presented the two slender 

 filiform setose palpi, and the slender horny seta at the base, as 

 represented in fig. 2 a** and -j- ; the proboscis itself was porrected 

 and as long as the head. The antennae are black, about three 

 times as long as the head, with the last joint flattened and pear- 

 shaped. The thorax is black, with the sides and two tubercles 

 at the anterior angles obscure red ; the scutellum is of the same 

 colour, the hind part of the thorax being black. The sides of 

 the mesothorax, before the halteres, are produced into two short 

 black porrected spines. The abdomen is long, and much narrowed 

 in its basal half; it is black, with the four anterior segments 

 marked on each side with a pale yellow spot ; the terminal ventral 



