PTEROMALIDAE OF N.W. EUROPE 183 



enough to allow the two genera to be kept distinct, but I have now found a species 

 which is intermediate as regards the flattening of the thorax between Isoplata 

 geniculata and normal species of Telepsogos. Hence I am uniting the two genera. 

 There are similar difficulties in distinguishing Telepsogos from Seladerma. The 

 type-species of Seladerma (and some other species of the genus) have the stigmal 

 vein of the fore wing curved and forming a relatively acute angle with the post- 

 marginal vein (Text-fig. 155), whilst the body is large and robust and the antennal 

 flagellum has relatively numerous sensilla. The type-species of Telepsogos (and 

 most other species of the genus) have the stigmal vein forming a relatively less 

 acute angle, whilst the body is relatively smaller and the antennal flagellum has 

 relatively sparse sensilla. These distinctions, however, do not work out 

 consistently. Seladerma convexum Walker, which in most respects is very like the 

 type-species S. laetum, has the stigmal vein at a less acute angle than usual ; whereas 

 S. saurns Walker, which in most respects is a typical Telepsogos, often has the 

 stigmal vein forming an angle as acute as in the type-species of Seladerma. As 

 other distinguishing characters appear to be lacking, I have decided to unite 

 Telepsogos with Seladerma. Seladerma, in the sense used in the present paper, may 

 be divided into several species-groups. 



Key to British and Swedish Species 

 (Females) 



1 Spur of mid tibia weak, its length hardly equal to the maximum breadth of 



the tibia. Antenna with combined length of pedicellus and flagellum 

 hardly greater than breadth of head ; funicular segments short, with 

 numerous sensilla arranged in one row on each segment. Thorax strongly 

 arched dorsally, scutellum in profile appearing convex 



simplex (Thomson) (p. 194) 



- Spur of mid tibia stronger, its length at least slightly greater than the 



breadth of the tibia. Antenna with combined length of pedicellus and 

 flagellum usually at least slightly greater than breadth of head, if hardly 

 greater than the thorax is weakly arched dorsally and the scutellum in 

 profile appears virtually flat ........ 2 



2 (1) Postspiracular sclerite with a more or less distinct oblique carina which marks 



off a triangular upper area ......... 3 



- Postspiracular sclerite without an oblique carina ..... 4 



3 (2) Either the scutellar frenum has some longitudinal carinulae ; or else the stig- 



mal vein (Text-fig. 155) forms a relatively acute angle with the postmarginal 

 vein. Gaster about twice as long as broad, usually slightly narrower than 

 the thorax ............ 28 



- Scutellar frenum reticulate, without longitudinal carinulae ; stigmal vein 



forming a relatively less acute angle with the postmarginal vein. Gaster 

 ovate, rather less than twice as long as broad, about as broad as the thorax . 4 



4 (3) Stigmal vein of fore wing (Text-fig. 155) strongly curved and forming an angle 



of only 35 to 40 with the postmarginal vein ; sensilla arranged in two 

 rows on at least some of the funicular segments ; scutellum (not counting 

 the frenum) and axillae, with engraved sculpture ; hind coxae bare dor- 

 sally ; gaster not longer than head plus thorax ; large species, 2-7 to 

 3 -6 mm. ............ 30 



