PTEROMALIDAE OF N.W. EUROPE 659 



reared from the seeds of various grasses. Morphological differences between forms 

 reared from different species of grass apparently exist but are very slight, particularly 

 in males. Von Rosen drew attention to small differences in the hypopygia (valvulae 

 ventrales) of their respective females and illustrated them by photographs. I have 

 examined the hypopygia of the forms occurring in Britain, and find small differences 

 which are suggestive and seem to be consistent with those visible in von Rosen's 

 figures. Even so I regard the problem as being far from settled. The hypopygia 

 of large number of reared specimens will have to be compared to ascertain whether 

 the differences are constant. Also, it has not been so far determined whether any 

 of the forms will cross with one another, nor are the details of their biology known. 

 Von Rosen has done very useful pioneer work in studying this complex, but much 

 still remains to be learnt. Keeping an open mind, I list here the forms which he 

 regards as sibling species, mentioning the characters which appear to have some 

 significance. If further research shows that some of the forms .are conspecific, the 

 synonymy can be adjusted accordingly. 



Mesopolobus teliformis (Walker) 

 (Text-figs. 544, 548, 551) 



Platyterma teliforme Walker, 1834 : 305, q* $. 



Platyterma cincticorne Walker, 1834 : 306, $ {nee $). 



Ptevomalus placidus Forster, 1841 : 11, $ [nee Walker, 1835a]. 



Eutelus {Platytermus) brevicornis Thomson, 1878 : 77, q" $. 



Pteromalus suavis Dalla Torre, 1898 : 149 [n. n. for placidus Forster nee Walker]. 



Platyterma teliforme Walker ; Graham, 19570" : 222 - 



Mesopolobus cincticornis (Walker) v. Rosen, 1958 : 213-214, o* ?• 



Mesopolobus teliformis (Walker) v. Rosen, 1958 : 214-215, <$ $. 



Mesopolobus laticomis (Walker) v. Rosen, i960 : 16-22 [ex parte] 



Mesopolobus laticomis (Walker) ; v. Rosen, 1960a : 29 [ex parte]. 



Mesopolobus teliformis (Walker) ; v. Rosen, 1962 : 142-144. 



Type material. Platyterma teliforme Walker and Eutelus brevicornis Thomson ; 

 lectotypes designated by Graham (1957^). 



Platyterma cincticorne Walker. Two males and one female stand under this name, 

 but the female disagrees with the description of that sex, which suggests a different 

 species. LECTOTYPE, the second male, bearing a Waterhouse label. Von Rosen 

 first (1958) regarded it as a distinct species, then (i960) synonymized it with laticomis, 

 and finally (1962) treated it as a form of teliformis. From the evidence which he 

 has presented, and from a study of the lectotype and my own material, I also believe 

 that it is a form of teliformis. The form cincticornis comprises large specimens of 

 teliformis in which the fiagellum is rather less clavate, and the first funicular segment 

 relatively larger, than in typical teliformis. 



Pteromalus placidus Forster. Syntypes presumably in Naturhistorisches Museum, 

 Vienna. The species was synonymized with teliformis (Walker) by von Rosen 

 (1962 : 142). 



