PTEROMALIDAE OF N.W. EUROPE 249 



Oxford (Type Hym. 17), labelled in Walker's handwriting " Micradelus rotundatus " 

 [sic] . 



Micradelus obscurus Thomson. Lectotype $ (Sweden, Lulea Lappmark) in 

 Universitetets Zoologiska Institution, labelled " Lpl " [Lapland]. In Kerrich & 

 Graham (1957 : 275) I regarded obscurus as a valid species and mentioned the 

 characters by which the lectotype <$ differed from that of rotundus Walker. Since 

 then I have seen other specimens which appear to bridge the gap between the two 

 and indicate that obscurus is merely a very large and robust example of rotundus. 



Boucek (1961) drew attention to the extreme variation of what he considered to 

 be rotundus Walker, in particular the shape of the female gaster, illustrating (fig. 6) 

 a female in which this is long-ovate in shape. He also refers to the variation of 

 the antennae in both sexes. For some time I had also been aware of considerable 

 variation of a similar kind in my own material placed under rotundus. I now think 

 that two species are involved because the variation does not appear to be 

 continuous ; the differences between them are summarized in my key. 



Britain, Sweden, Czechoslovakia. 



Biology. Unknown. My own specimens have for the most part been swept in 

 open situations (grassland, including chalk downland). Imagines May-June. 



Micradelus acutus sp. n. 



Micradelus rotundus Boucek, 1961 : 62, [ex parte] ; fig. 6, $ [nee Walker, 1834]. 



9. Differs from that of rotundus Walker as follows : 



Body smaller and rather less robust ; gaster longer and acute or even slightly acuminate 

 apically, the last tergite being triangular. Antenna (Text-fig. 188) with flagellum rather more 

 clavate, the funicle more slender proximally ; only four (instead of five) funicular segments. 

 Head in dorsal view only 1 -95 to 2 times as broad as long ; temples rather longer, about one 

 third as long as eyes, and slightly more bulging. Fore wing with stigmal vein tending to be 

 slightly curved, straighter in rotundus ; uncus on the average rather shorter ; marginal vein 

 1-2 to 1-5 times as long as the stigmal vein. 



<J. Differs from that of rotundus in the characters given in the key above. 



Holotype $. England : Oxfordshire, Bald Hill, near Lewknor, 22. v. i960, on 

 chalk downland [Graham), in the Hope Dept., University Museum, Oxford. 



Paratypes. Same locality as holotype, 3 <£, 2 $, 22. v. i960, 2 $, 2.VL1957, on 

 chalk downland ; Berkshire, Wytham, 1 <$, 26. v. 1955, 3 $, 7. v. i960, all swept in 

 a damp meadow between Wytham Wood and the River Thames [Graham). 



Biology. Unknown. 



TERMOLAMPINI 

 TERMOLAMPA Boucek 



Termolampa Boucek, 1961 : 60-61. Type-species : T. pinicola Boucek by monotypy and 

 original designation. 



Boucek (1961 : 61) proposed a new tribe, Termolampini, of the Tridyminae, for 

 the reception of this genus. This seems to be a natural arrangement. 



