PTEROMALIDAE OF N.W. EUROPE 297 



Type material. Gastrancistrus hamillus Walker. One female, LECTOTYPE, 

 with Waterhouse label. 



Tridymus flavipes Thomson. Syntypes, 6 specimens. LECTOTYPE, a female 

 labelled " Sm " [Smaland] and " Bhn " [Boheman]. 



Britain, Sweden. I take it not uncommonly from the foliage of Salix species, 

 also occasionally from that of Betula. 



Biology. Unknown. Imagines July-August. 



Gastrancistrus acontes Walker 



(Text-fig. 250) 



Gastrancistrus Acontes Walker, 1840 : 32, q*. 

 Tridymus convergens Thomson, 1876a : 199, ?, syn. n. 



Type material. Gastrancistrus acontes Walker. LECTOTYPE (? holotype) <$ 

 in Greville coll., Edinburgh, stand' ng above a label " Gastrancistrus Acontes W. s. n. 

 fide Wk. Edinb." ; the specimen also bears a red-bordered Type label and another 

 reading " Greville 1936-50. 290 ". 



Tridymus convergens Thomson. Syntypes, 4 specimens. LECTOTYPE, a 

 female labelled " L-d " [Lund] and " convergens Ths " ; also bearing A. Jansson's 

 lectotype-label. 



Britain, Sweden, apparently rare. 

 Biology. Unknown. Imagines in June. 



The AUTUMN ALIS-Grovp 



Gastrancistrus autumnalis (Walker) 

 (Text-fig. 227) 



Glyphe autumnalis Walker, 1834 : 171, $. 

 Gastrancistrus autumnalis (Walker) Walker, 1846 : 25. 

 Tridymus productus Thomson, 1876a : 196, $, syn. n. 



Type material. Glyphe autumnalis Walker. Two specimens stand here, but one 

 is probably not original material. The other, a female with a Waterhouse label, 

 also labelled " Type " in A. B. Gahan's handwriting, is designated LECTOTYPE. 



Tridymus productus Thomson. Syntypes, 2 females. LECTOTYPE labelled 

 " V.G." [Vestra Gottland], " Bhm." [Boheman] and " productus ". 



Britain, Ireland, Sweden. Occurs commonly on the foliage of Fagus sylvatica 

 L. in the autumn. Walker (1834 : I 7 I ) nrs ^ recorded it "on flowers of the ivy ; 

 near London " ; I have taken it in the same situation. 



Biology. Host unknown, but seems likely to be some Cecidomyiid associated 

 with Fagus. Imagines Sept.-Oct. 



Gastrancistrus oporinus sp. n. 



$. Head and thorax dark green ; gaster bronze-black, with greenish or bluish reflections on the 



