PTEROMALIDAE OF N.W. EUROPE 495 



Habrocytus Thomson ; Kurdjumov, 1913 : 9, 18-21 [ex parte]. 

 Habrocytus Thomson ; Nikol'skaya, 1952 : 231 [ex parte]. 

 Habrocytus Thomson ; Peck et al., 1964 : 58. 



The identity of Colas Curtis has not hitherto been recognized in any publication, 

 though for some years I have known that its type-species belonged to the genus 

 which is generally known as Habrocytus Thomson. In view of the widespread 

 usage of the latter name, and also because Habrocytus is in any case perhaps doubt- 

 fully distinct from Pteromalus, I reject Colas Curtis although it has priority. On 

 the other hand it is possible that at some future time, the species-group of 

 Habrocytus to which the type-species (dispar Curtis) of Colas belongs, may be 

 regarded as a good genus ; in that case the name Colas would be available for it. 



It is quite difficult to construct a workable key to the species of Habrocytus and 

 Pteromalus, even when only the British species are taken into consideration. This 

 is due to the considerable variation presented by some characters. Those used in 

 the following key to females have resulted in what is, I believe, a fairly natural 

 grouping of the species within the key, although this was not a primary aim. Hence 

 one hopes that it may be a reasonably sound basis for work on the European species. 

 The latter will undoubtedly prove to be very numerous, consequently the difficulties 

 already apparent will increase. I have included Habrocytus and Pteromalus in a 

 single key because at present I know of only one character (the number of teeth 

 in the mandibles) which will separate them. This character cannot always be 

 seen and is therefore not a practical one. It should be noted that I have examined 

 the mandibular teeth in all the species included in the key ; those having 4 teeth in 

 both mandibles have been referred to Pteromalus, those with 3 teeth in the left 

 mandible to Habrocytus. The number of teeth appears to be very constant within 

 the species. Rarely aberrations occur, however, and these are somewhat 

 embarrassing. For example, I possess a female of Habrocytus isarchus (Walker) 

 which has 4 teeth in both mandibles! Logically the best course might be to unite 

 both genera under Pteromalus, but as Habrocytus is so well known I hesitate to do 

 this at present. 



The males of many of the species are known to me. Some present very good 

 and obvious characters, but more often the males of allied species are very difficult 

 to separate. I consider it advisable to await the study of more extensive, and in 

 particular, bred material before attempting to publish a comprehensive key to the 

 males even of British species. A tentative key to some of the more easily recogniz- 

 able species is given, however ; it should help to assign a number of males at least 

 to their correct species-group. 



An exhaustive study of Habrocytus, perhaps the largest genus of Pteromalidae, 

 would itself be almost the work of a lifetime. 



HABROCYTUS Thomson and PTEROMALUS Swederus 

 Key to British (and some other European) Species 

 (Females) 

 1 Lower edge of antennal toruli not or hardly above the level of the ventral 



