PTEROMALIDAE OF N.W. EUROPE 391 



lus and flagellum at most equal to the breadth of the head. Marginal vein 

 of fore wing of uniform thickness throughout, or slightly thicker at apex 

 than at base ........... 22 



- Antennae with flagellum filiform ; combined length of pedicellus and 



flagellum usually greater than breadth of head. Marginal vein at least 



very slightly thicker at base than at apex . . . . . . 23 



22 (21) Fore wing with postmarginal vein at least slightly shorter than the marginal 



vein, and sometimes not longer than the stigmal vein ; marginal longer 

 than the stigmal (cf. Text-fig. 323). Hind coxae pilose dorsally, virtually 

 to base METACOLUS Forster (p. 418) 



- Fore wing with postmarginal vein as long as or longer than the marginal vein, 



the latter not longer than the stigmal vein. Hind coxae dorsally usually 

 bare in their basal half, occasionally with one or two hairs 



RHAPHITELUS Walker (p. 420) 



23 (21) Anterior margin of clypeus incised medially, with a rounded lobe on either 



side of the incision. Hind tibia with two spurs. Propodeum medially 

 somewhat shiny, weakly reticulate . CAENOCREPIS Thomson (p. 429) 



- Anterior margin of clypeus truncate or virtually so. Hind tibia with one 



spur. Propodeum medially strongly reticulate and relatively dull 



HOMOPORUS Thomson (p. 444) 



24 (12) Antennae with two anelli : usually with six funicular segments, occasionally 



seven, rarely eight .......... 25 



- Antennae with three anelli and five funicular segments . . . .159 



25 (24) Marginal vein of fore wing (Text-fig. 291) conspicuously and rather abruptly 



thickened in its proximal half ........ 26 



- Marginal vein either not thickened, or at most thickening very gradually 



towards its base .......... 27 



26 (25) Antennae inserted low on head, lower edge of toruli about level with ventral 



edge of eyes ; head protuberant at level of toruli 



MUSCIDIFURAX Girault & Sanders (p. 822) 



- Antennae inserted higher on head, lower edge of toruli at least slightly above 



level of ventral edge of eyes ; head not protuberant . . . . 27 



27 (26) Temples with a shiny band which extends from base of mandible to vertex 



(Text-fig. 574) PERIDESMIA Forster (p. 701) 



- Temples without a shiny band . . . . . . . .28 



28 (27) Mid tibia either conspicuously expanded, and at least partly flattened ; or 



with a process on its outer edge. Face and clypeus without conspicuous 

 piliferous punctures .......... 29 



- Mid tibia neither conspicuously expanded nor with a process, if slightly 



expanded, then face below toruli, and clypeus, with conspicuous piliferous 

 punctures amongst the reticulation . . . . . . . 31 



29 (28) Propodeum with a large, quite strongly reticulate nucha, often also with a 



costula ; dorsal surface of hind coxae with some hairs in its basal half 



SPANIOPUS Walker (p. 702) 

 Propodeum with nucha represented only by a short, transversely lunate, weakly 

 aciculate or smooth strip ; dorsal surface of hind coxae bare in its basal 

 half ............ 30 



30 (29) Mid tarsi proximally somewhat expanded and flattened, tapering distally. 



Body dark or bronze-green ; legs extensively infuscate ; antennae brown 



or testaceous PEGOPUS Forster (p. 684) 



- Mid tarsi neither expanded nor flattened. Body bright green to blue ; legs 



and antennae mainly to wholly yellow MESOPOLOBUS Westwood (p. 638) 



