u6 M. W. R. de V. GRAHAM 



The female differs from those of maculatus Erdos and unicolor sp. n. in the characters given 

 in my key to species. 



o*. Differs from the female as follows : 



Length 1-7 to 2 mm. Antennal scape (except proximally) more brownish tinged ; pedi- 

 cellus darker than in the female ; clypeus, genae, and lower face greenish with only a slight 

 bronze tinge. 



Antennae (Text-fig. 84) with scape not quite reaching the level of the median ocellus, slightly 

 more than three times as long as broad, its length somewhat less than the transverse diameter of 

 an eye, only very slightly expanded just above the middle, where there is a small shiny boss on 

 its anterior margin ; combined length of pedicellus and flagellum about 1 -8 times the breadth 

 of the head ; pedicellus rather shorter (i-6 to 1-7 times as long as broad) ; funicle proximally 

 slender, hardly as stout as the pedicellus in profile, but thickening slightly distad, its first seg- 

 ment about 2-5 times, sixth segment about twice, as long as broad ; clava about three times 

 as long as broad, slightly broader than the sixth funicular segment, its length about equal to 

 that of the two preceding funicular segments together ; flagellum with few sensilla, which are 

 relatively long but placed in a single row in the distal part of each segment ; funicle clothed 

 with long bristly hairs which stand out at an angle of about 30 , their length being somewhat 

 greater than the breadth of the segments which bear them ; on the clava the hairs are similar 

 but decrease somewhat in length. 



Metapleuron with only two to six hairs. Lower surface of costal cell of fore wing in one 

 specimen with three to four hairs in the proximal third. 



Gastral petiole about as long as broad, about two thirds as long as the propodeum. Gaster 

 oblong-sublinear, as long as but somewhat narrower than the thorax, ventrally concave with 

 a median plica. 



Holotype $. England : Norfolk, 10.vii.1955, reared from logs of Alnus glutinosa 

 L. {G. H. Thompson), BM(NH). 



Paratypes. England: Norfolk, 1 <$, 7.vii.ig55, 1 $, 10.vii.1955, reared from logs 

 of Alnus glutinosa L. (G. H. Thompson), BM(NH). 



The holotype $ is labelled " Alnus glutinosa Cage No. : 21 10 July 1955 " ; 

 " England G. H. Thompson B.M. 1956-194 " ; and " Platygerrhus ductilis Walk. 

 $ " July form " G. J. Kerrich det. 1955 ". 



Biology. Unknown. 



Platygerrhus unicolor sp. n. 



$. Differs from that of subglabersp. n. as follows : 



Lower part of head not tinged with purplish bronze. Fore wings immaculate in the British 

 specimens, but in the Czechoslovak female with a fuscous cloud anterior to the stigmal vein. 

 Clypeus alutaceous, only its anterior margin polished ; genae sculptured, except for a strip 

 immediately behind the malar sulcus ; malar space longer, somewhat more than one third 

 the length of an eye. Antennal scape reaching the level of the vertex, its length very slightly 

 greater than the transverse diameter of an eye. 



Dorsellum rather more shiny and less strongly sculptured, its hind margin smooth. Meta- 

 pleuron with seven to ten hairs scattered over its surface. Mesepimeron with rather stronger, 

 slightly raised, sculpture. Fore wing with lower surface of costal cell with a complete, even 

 partially double, row of hairs extending to its base, also with more numerous scattered hairs in 

 the distal half ; basal cell closed below in about its distal half by a line of hairs on the cubital 

 vein, and with a few hairs below the submarginal vein. 



