PTEROMALIDAE OF N.W. EUROPE 323 



Gaster oval, depressed dorso-ventrally, nearly as long as and broad as the thorax, about 1 -5 

 times as long as broad, obtuse apically ; dorsally slightly to distinctly sunken on the disc, the 

 basal tergite with a semicircular fovea which has a median longitudinal ridge ; last tergite very 

 short, much broader than long ; ovipositor sheaths concealed in dorsal view ; ventrally the 

 gaster is strongly convex and keeled, with the tip of the hypopygium situated at about the 

 middle. 



cJ. Unknown. 



In general fades, and particularly in the shape of the gaster, aequus much resembles 

 pusztensis (Erdos), but differs in its darker antennal flagellum, relatively longer 

 marginal vein, shorter postmarginal vein, and in having the scutello-axillar sutures 

 only slightly convergent. From all the other species having the latter character, 

 it differs in the shape of the gaster (see couplet 34 of key to species), though in other 

 respects it much resembles laticeps sp. n. 



Holotype $. England : Berkshire, Bagley Wood, 30. v. 1954, swept from mixed 

 herbage (Graham), in Hope Department, University Museum, Oxford. 

 Paratype. Same data, 1 $, in Graham collection. 

 Biology. Unknown. 



The COMPRESS C/S-Group 



Gastrancistrus compressus Walker 



(Text-fig. 266) 



Gastrancistrus compressus Walker, 1834 : 172, o*. 



Tridymus pallicornis Thomson, 1876a : 200, $, syn. n. [pre-occupied by Gastrancistrus pallicornis 



Walker, 1872 : n6, ?.] 

 Gastrancistrus tiwmsonii Dalla Torre, 1898 : 205 [n. n. for G. pallicornis Thomson nee Walker]. 



Type material. Gastrancistrus compressus Walker. Syntypes, 2 <J. LECTO- 

 TYPE, one bearing a Waterhouse label, also one in C. Ferriere's handwriting " Type 

 C.F.". 



Tridymus pallicornis Thomson. Syntypes, 7 specimens. LECTOTYPE, a female 

 labelled " Ar 6/56 " ; the specimen has been remounted by A. Jansson and also 

 bears his lectotype-label. 



Britain, Sweden. In England it is not uncommon in pastures and meadows. 

 Biology. Unknown. Imagines June- August. 



Gastrancistrus glabellas (Nees) comb. n. 



(Text-fig. 267) 



Eulophus glabellus Nees, 1834 : 187, $. 



Tridymus laeviscuta Thomson, 1876a : 200, $, syn. n. 



Gastrancistrus leviscuta Dalla Torre, 1898 : 204 [emendation]. 



Type material. Eulophus glabellus Nees. One female, from the collection of 

 Nees, exists in the Westwood collection in the Hope Department, University 

 Museum, Oxford. It bears a small pink square with the number " 12 "; a label 



