PTEROMALIDAE OF N.W. EUROPE 605 



margin of the clypeus ; fiagellum virtually filiform, with sixth funicular 

 segment quadrate. 



Malar space fully half the length of an eye or even slightly more 



sp. indet. A. (p. 609) 

 Antennal toruli about equidistant from the median ocellus and the anterior 

 margin of the clypeus ; fiagellum (Text-fig. 479) thickening slightly distad, 

 sixth funicular segment quadrate to slightly transverse . . . . 14 



14 (13) Malar space slightly less than half the length of an eye ; pronotal collar often 

 weakly margined, if sharply so, then rarely over more than about the middle 

 third ........ micans (Olivier) (p. 609) 



Malar space half the length of an eye ; pronotal collar very sharply and 



strongly margined, except just at the sides . . . iera (Walker) (p. 609) 



(Males) 



1 Anterior margin of clypeus (Text-fig. 469) with a median tubercle only. 



Antennal scape slightly shorter than the transverse diameter of an eye, not 

 or only just reaching the level of the lower edge of the median ocellus. 

 Marginal vein of fore wing more than twice as long as the stigmal vein ; 

 postmarginal vein obviously shorter than the marginal. All coxae metallic ; 

 legs fairly stout ; spur of mid tibia half the length of the first tarsal segment 



cf. Chlorocytus formosus (Walker) (p. 619) 

 Anterior margin of clypeus (Text-fig. 468) with a median tooth and a small 

 projection on each side of it, some dwarfs of muscarum have these projections 

 very weak, but in this species the antennal scape is much longer, and the fore 

 and mid coxae are flavous. Marginal vein of fore wing often rather less 

 than twice as long as the stigmal vein ; postmarginal vein sometimes hardly 

 shorter than the marginal ......... 2 



2 (1) Fore and mid coxae flavous. Mesosternum, except the fore coxal acetabula, 



thickly clothed with subadpressed white hairs, these being particularly 

 dense just in front of the mid coxae. Antennal scape virtually as long as 

 an eye, reaching slightly above the vertex, tending to be a little broader in 

 its lower part. Marginal vein of fore wing rather more than twice the 

 length of the stigmal vein ; postmarginal vein distinctly shorter than the 

 marginal ....... muscarum (L.) auctt. (p. 611) 



All the coxae metallic, or at most the fore coxae testaceous or reddish on their 

 inner aspect. Mesosternum with a bare patch on either side of the mesol- 

 cus ; the hairs that clothe the rest of the surface are not so thickly distribu- 

 ted as in muscarum, and are slightly outstanding. Antennal scape at least 

 very slightly shorter than an eye, not broadest in its lower part, though 

 often slightly expanded in its upper part ...... 3 



3 (2) Temples, in dorsal view of the head, converging only slightly, more than one 



third as long as the eyes. Malar space half the length of an eye or even 

 rather more. Large species, usually 4 to 5 mm. in length ; head and 

 thorax green varied with coppery or crimson . . liparae (Giraud) (p. 607) 



Temples converging relatively strongly, and relatively shorter than in the 

 above. Malar space often less than half the length of an eye. Species 

 usually smaller than the above, or else the head and thorax without coppery 

 or crimson tints .......... 4 



4 (3) Antennal scape nearly as long as an eye, with a slightly projecting shiny carina 



or boss extending over the upper half of its anterior edge ; antennal toruli 

 placed approximately midway between the anterior margin of the clypeus 

 and the median ocellus ; marginal vein of fore wing 1 -8 to 1 -85 times as long 



