Anthomyid genera Hammomyia and Hylephila. 309 



oral margin very small and uniserial. Pre-alar bristle shorter. 

 Bristles on legs niuch less conspicuous; often a tiny bristle above 

 front tibiae on ajiical third. Mid femora with only 1-2 very short 

 posteroventral bristles near base instead of the 4-5 long ones of 

 male. Hind femora with incomplete anteroventral row of bristles 

 and these short except towards tip. Hind tibiae bare behind. 

 Length 3 "5 — 6 mm. 



H. albescens is more often met with than H. grisea. 

 Sjiecimens have been examined for tlie purpose of this 

 paper from Hampshire, Essex, Suffolk, Cambs, Norfolk, 

 London and Nottinghamshire, taken in June, July and 

 August. They occur in sandy places in association with 

 Aculeate Hymenoptera. The females are very difficult to 

 distinguish from those of H. sociata, and both species occurred 

 together to the late Mr. Verrall at a sandy cutting by 

 Plumstead railway station near Woolwich on July 17th, 

 1874. Zetterstedt gives Diodontus pallipes as the host, 

 and an old note of Mr. Verrall's states that Mr. Charbonnier 

 of Bristol found H. albescens * ovipositing in the burrows of 

 Halictus nitidiiisculus. In Kertesz' Catalogue the name 

 of albiseta v. Roser (1840) is used by Stein for this species. 

 In view of the fact that a still older name {cinerea Desv. 

 1830) is quoted as a synonym in the same Catalogue, 

 which so far as the descriptions are concerned appears tp 

 have as much right to be used as that of von Roser, it 

 is not proposed to discontinue the use in the British List 

 of Zetterstedt's well-known name. 



3. H. sociata Meigen, Beschr. Eur. Dipt, v, 98 (1826). 

 Syn. gallica Schnbl. and Dzied., Nova Acta, xcv, 236 and 

 355 (1911). 



(Plate VII, fig. 2.) 



c^. Eyes very narrowly separated on frons by the narrow orbits 

 and frontal stripe. Head in profile with a projecting frons, the 

 facial oibits opposite base of antennae very wide but rapidly 

 narrowing below. Face short and slightly retreating. Jowls with 

 numerous upcurved bristles above oral margin in many rows. 

 Lower part of occiput considerably inflated. The silvery frontal, 

 and upper part of facial, orbits with distinct blackish reflections 

 in some lights. Thorax brownish-grey with (in some lights) five 



* The possibihty that Charbonnier's specimens might have been 

 the next species {sociata) must not be overlooked. 



