310 Mr. J. E. Collin's Contribution toivards knowledge of 



blackish stripes, the side stripes being broad, but they all vary 

 according to the point of view, and when viewed from behind 

 the intermediate stripes disappear. Scutellum also with shifting 

 dark tessellations. Behind the humeri there are other bristles in 

 addition to the usual intrahumeral and presutural, notably a very 

 strong ( ? true posthumeral) bristle nearer the notopleural depres- 

 sion. Pre-alar bristle long and distinct. A pair of presutural 

 acrostichal bristles much stronger than the others. Often a third 

 shorter finer bristle below the usual two posterior sternopleuial 

 bristles. Abdomen light brownish- (almost yellowish-) grey, with 

 a narrow dark central stripe. Tessellations not conspicuous, but 

 in some lights a distinct darkening about sutures. Front femora 

 rather densely long-haired behind; front tibiae with two bristles 

 behind on apical half. Middle tibiae with no bristle beneath. 

 Hind femora with a complete anteroventral row of long bristles 

 and with 2-4 similar or even longer bristles posteroventrally on 

 basal half; hind tibiae with 2-3 short bristly hairs behind. In 

 other respects the chaetotaxy is as usual in this group. Wings 

 absolutely without costal spine; cubital and discal veins slightly 

 converging except at their extreme tips; postical cross- vein very 

 oblique and remarkably sinuate. Squamae (subequal) and hal teres 

 yellow. 



$. Differing completely in colour from the male, being grey and 

 remarkably like the female of albescens. The frons is always 

 slightly wider, being {\^ the width of the head and approximately 

 I wider than in albescens. Palpi narrower at the base and more 

 distinctly dilated and flattened about middle and more pointed 

 towards tip than in albescens. The thorax is rather more distinctly 

 striped, the middle stripe appearing in some lights to split up into 

 two closely approximated dark lines. The abdominal stripe may 

 almost disappear when viewed in certain lights — much more so 

 than in albescens. 



Length 6-7 mm. 



H. sociata is here for the first time introduced as British 

 on five females (two in the British Museum and three in 

 the writer's Collection), after a close comparison with 

 Continental specimens kindly supplied by Dr. Villeneuve, 

 who has taken both sexes near Rambouillet (Seine-et-Oise). 

 Four of the British specimens were captured by the late 

 Mr. Verrall close to Plumstead railway station near 

 Woolwich, in company with H. albescens, on July 17th, 

 1874; the fifth is an old specimen from Dossiter's Col- 

 lection without locality. Though there is little doubt 



