PTEROMALIDAE OF N.W. EUROPE 461 



Merisus (Baeotomus) plagiatus (Nees) Thomson, 1878 : 61, o" 9- 



Callitula bicolor Spinola 

 Callitula bicolor Spinola 

 Callitula bicolor Spinola 

 Callitula bicolor Spinola 

 Callitula bicolor Spinola 



Hill & Smith, 1928 : 153-155. 

 Imms, 1932 : 443-447. 

 Gahan, 1933 : 109-114,0* ?. 

 Peck, 1963 : 652-653. 

 Boucek, 1964 : 10-11, £ $. 



Type material. Callitula bicolor Spinola. Location of types, if extant, not 

 known. Synonymized by Nees (1834 : 115) with his Pteromalus plagiatus, which 

 is the present species. The name bicolor Spinola has been generally accepted since 

 its adoption by Gahan (1933). 



Micromelus rujomaculatus Walker. Six specimens stand under this name (but 

 probably some are not original material). LECTOTYPE, a female bearing a label 

 " 1045 ", also a Waterhouse label. 



Pteromalus plagiatus Nees. LECTOTYPE $ in West wood coll., Oxford (ex 

 coll. Nees). It bears the following labels : a pink one with the number " 8 " ; one 

 in the handwriting of Nees " D. 48. b (25) plagiata mihi $ 2. N. 12 " ; another 

 in Westwood's handwriting " Pteromalus plagiatus Es. 2. 115. Callitula bicolor 

 Spin. E Mus. Esenb ". Nees himself cited Callitula bicolor Spinola as a synonym 

 of plagiatus, but seems to have regarded Spinola's name as a nomen nudum. It is 

 just possible that Nees may have seen Spinola's types of bicolor, because he mentions 

 (1834, passim) having been sent material of other species by that author. 



Thomson (1878 : 61) cited " Pteromalus futilis Foerster " as a synonym of 

 plagiatus [=bicolor]. There is no Forster species having this name ; probably 

 Thomson meant mutilus Forster which, however, is almost certainly the same as 

 C. pyrrhogaster , see below. 



C. bicolor was redescribed in detail and figured by Gahan (1933), also by Imms 

 (1932). 



Widely distributed in Europe ; North America. 



Biology. The species is a primary or secondary parasite of various small Diptera 

 in stems of Gramineae. It has been reared in Europe and North America from 

 Mayetiola destructor (Say) (Cecidomyiidae) ; and from the following Chloropidae : 

 from Chlorops taeniopus Mg. and Lasiosina cinctipes Mg. in U.S.S.R. ; Meromyza 

 americana Fitch in North America, M. saltatrix (L.) in U.S.S.R., seine! la frit (L.) 

 in Europe and North America, 0. minor (Adams) in North America, possibly also 

 0. carbonaria (Low) and 0. soror (Macq.) in North America. C. bicolor has also 

 been recorded as a hyperparasite, attacking Proctotrupoidea (Platygasteridae) 

 which are primary parasites of the above Diptera : e.g., Platygaster vernalis (Myers) 

 and P. zosine Walker, in U.S.S.R. and North America. Females evidently hibernate 

 in Britain ; Mr. Gradwell and I have both found females during the winter in grass 

 tussocks (particularly of Deschampsia caespitosa). I have rarely found any other 

 Chalcidoid (except Cyrtogaster vulgaris) hibernating in grass. In Britain adults of 

 bicolor also occur in the field from May until October ; probably therefore more 

 than one brood per annum. 



