PTEROMALIDAE OF N.W. EUROPE 831 



Pachyneuron. The insect shown in the figure was described by DeGeer in his 

 17th Memoir, section 8, p. 604, and he obtained it from some parasitized 

 " Gallinsectes " which he had found on elm ; his figure 14 on pi. 35, representing 

 this " Gallinsecte " shows what appears to be a Lecaniine Coccid. 



Key to European Species 

 (Males and Females) 



1 Fore wing with apical margin without cilia ; postmarginal vein only slightly 



longer than the stigmal vein ; marginal vein strongly thickened, only 

 about 1-25 times as long as its maximum breadth. Pronotal collar some- 

 times immarginate. Antennal scape not reaching the median ocellus. 

 Gastral petiole slightly transverse, subconical. . aeneum (Masi) (p. 834) 



Fore wing with apical margin ciliate ; postmarginal vein 1 -5-2 times as long 

 as the stigmal vein ; marginal vein less strongly thickened, 2-7-4 times 

 as long as its maximum breadth. Pronotal collar nearly always distinctly 

 margined, very weakly so in some dwarfs. Antennal scape often reaching 

 the median ocellus. Gastral petiole sometimes otherwise ... 2 



2 (1) Thorax weakly arched dorsally ; scutellum in profile nearly flat, its disc with 



weaker sculpture, hence more shiny, than the rest. Marginal vein of fore 

 wing 1-3-1-4 times as long as the stigmal vein. Genae only slightly com- 

 pressed, hardly sharp-edged above the bases of the mandibles, and with 

 only a small hollow. Head in frontal view about 1-5 times as broad as high 



planiscuta Thomson (p. 834) 

 Thorax usually moderately to strongly arched dorsally with the scutellum 

 convex ; if not, then the scutellum is distinctly reticulate all over. 

 Marginal vein of fore wing at most 12 times as long as the stigmal vein. 

 Genae usually very distinctly compressed and sharp above the bases of the 

 mandibles, usually with a larger hollow. Head in frontal view usually less 

 transverse ............ 3 



3 (2) Median produced portion of clypeus (Text-fig. 678) having its anterior margin 



slightly emarginate or truncate, and its surface virtually flat ... 4 



- Median produced portion of clypeus (Text-fig. 678) having its anterior margin 



obtuse or rounded, and its surface convex in the transverse axis . . 9 



4 (3) Gastral petiole slightly broader than long, smooth or virtually so. Thorax 



very strongly arched dorsally ; dorsellum and propodeum sloping at an 

 angle of about 80 ° relative to the tangential plane of the mesoscutum and 

 scutellum. Gena with only a very weak lamina above the base of the 

 mandible ....... gibbiscuta Thomson (p. 838) 



Gastral petiole at least slightly longer than broad, mainly reticulate or trans- 

 versely aciculate. Thorax less strongly arched dorsally ; dorsellum and 

 propodeum sloping at a relatively less steep angle. Gena often with a 

 stronger lamina above the base of the mandible ..... 5 



5 (4) Fore wing with speculum closed below ; upper surface of costal cell with a 



row of hairs extending over its distal quarter to one third. 



$ clypeus, Text-fig. 677 ; antenna excluding scape, Text-fig. 679 



solitarium (Hartig) (p. 838) 



- Fore wing with speculum open below ; upper surface of costal cell often bare 6 



6 (5) Thorax relatively weakly arched dorsally, scutellum in profile appearing only 



weakly convex ; propodeum sloping at an angle of only 3o°-35° relative 

 to the tangential plane of the mesoscutum and scutellum. Propodeum 

 only slightly more than half as long as the scutellum ; nucha mainly 



