1001.] 243 



brief, besides being inaccessible to the majority o£ English Dipterists, 

 the following re-description will ])erhaps not be considered super- 

 fluous : — 



Pachygaster meromelcena, Duf. 



Pachygaster meromelas* L. Dufour: — " Annales des Sciences 

 Naturelles," Seconde Serie, T. xvi (1841). Zoologie, p. 2G6. 



Length, 3| mm. (1| 1.) ; length of wing, 3f mm.; width of head in $ slightly 

 more than 1 mm. 



Shining hJack ; thorax (including scutellum) in (^ clothed with very short ap- 

 pressed silvery white hairs ; in ? these hairs confined to a somewhat crescentic urea, 

 spreading out on side of thorax belmv, in front of the prominent post-sutural tubercle 

 on, each side; eyes unde apart in both sexes (front in 9 nearly tiuice the width of 

 that in $ , and broader above; in ^ practically uniform in width throughout), 

 each bordered anteriorly with a conspicuous silvery-iohite stripe, extending well 

 above base of antenna ; mesopletira ivith a vertical stripe of short silvery-white 

 hairs ; halteres in both sexes white, the stalk infuscated ; legs pale yellow, femora, 

 except the tips, black ; wings hyaline, the portion of the rosfa and of the first vein 

 before the pale yellow stigma blackish. 



Head and eyes shaped as in the ? of Pachygaster Leachii, Curt., conspicuously 

 larger and broader tlian in the ? of P. atra,Vz. ; the eyes are distinctly larger and 

 more prominent in tlte g than in the ? , and the whole head is in consequence 

 noticeably larger in the former sex. Antenna' in both sexes ochraceous, third joint 

 blackish at the apex and on the inner side, considei'ably larger in the $ than in the 

 cJ ; arista blackish. Eyes in life with a median horizontal purple band, extending 

 four-fifths of the way across from the front margin ; posterior orbits in the occipital 

 region practically invisible in the $ but somewhat more prominent in the ? , though 

 not produced to anything like the same extent that they are in the $ of P. air a. 

 Dorsum of thorax finely punctured, with the post-sutural tubercle on each side, seen 

 in P. Leachii but less noticeable in P. atra, very prominent; in the $ the anterior 

 portion of the central ai-ea of the dorsum of the thorax is clothed with minute 

 blackish hairs, which are much finer than the short silvery hairs clothing the same 

 region in the $ and also seen on the sides in the $ , in front of the post-sutural 

 tubercles ; posteriorly, between the tubercles and extending as far as the hind 

 margin, the minute hairs in the ? have a golden hue. Abdomen closely punctured, 

 clothed with minute blackish hairs. 



In the infuscated area of the third joint of the antennae each annulus is marked 

 with a series of circular yellow spots, which perhaps indicate sense organs; these 

 spots are quite conspicuous, even under a lens magnifying only ten diameters. 



When the males described above were running about alive in a glass tube the 

 silvery appeai'ance of the thorax, due to the character of the hairs clothing it, was 

 very noticeable. 



The above description is based upon an examination of three 

 males and five females bred from pupse found with a niiiuber of larvae 



* meros, upper part of the tbigh ; melas, black. 



