308 Mr. J. E. Collin's Contribulioii towards knowledge of 



H. grisea is not a common species in Britain. Specimens 

 have been examined captured during July and August, at 

 Studland (Dorset), by the late Mr. Verrall; in the New- 

 Forest (Hants) by Dr. D. Sharp, Mr. C. G. Lamb and 

 Mr. A. H. Hamm; at Golspie (Sutherland), and Waterville 

 in Ireland, by Col. J. W. Yerbury. There is also a specimen 

 in the Cambridge University Museum from Aberfoyle 

 (Perthshire). Miss L. H. Huie has recorded it from 

 Scotland, and fully described its life-history in the 

 " Scottish Naturalist " for January 1916, pp. 13-20. The 

 eggs are laid on the floor of the burrows of Andrena analis 

 near the exit. The female fly, after watching for a bee 

 laden with pollen, follows it to its burrow, and waits 

 near the mouth until the bee has left, when, after a hasty 

 examination, the fly backs into the burrow and lays an 

 egg. The grub when hatched Hves on the pollen mass 

 in the burrow. There is only one generation in the year, 

 the winter being passed in the pupal stage. 



Mr. A. H. Hamm found this species in the New Forest 

 about the burrows of the Andrenid, Panurgus calcaratus 

 Scop., and the fossorial wasp, Cerceris arenaria L. 



Previously considered a Hylemyia, this species was first 

 correctly placed in the genus Hammomyia by Schnabl. 



2. H. albescens Zetterstedt, Dipt. Scand. iv, 1520 (1845). 

 (Plate VII, fig. 3.) 



^. Frons about 2\ times the width of thhd antennal joint. 

 Orbits and frontaha silvery grey in most hghts. Vertical and 

 ocellar bristles fine and hairlike. Upcurved bristles on oral margin 

 in two rows. Thorax dull grey and usually only when viewed from 

 behind with indications (sometimes very faint) of a narrow brown 

 central stripe and broader side stripes from humeri to post-alar 

 calli. A single pair of presutural acrostichal bristles very strong. 

 Pre-alar bristle ^| as long as supra-alar. Abdomen distinctly 

 tessellated and with a narrow dark brownish central stripe, and 

 strong hind-marginal bristles. Hind femora with a complete 

 anteroventral row of bristles, but short-haired ijosteroventrally. 

 Front tibiae with two bristles behind placed fairly close together. 

 Middle tibiae without a bristle beneath. Hind tibiae with 3-4 

 short bristles behind. Wings with the postical cross-vein very 

 oblique and slightly undulated. 



$. Much resembling the male. Frons wider — slightly more than 

 half as wide again. All biistles shorter, the upcurved bristles on 



