PTEROMALIDAE OF N.W. EUROPE 837 



Pteromalus incubator Forster, 1841 : 28, <J. 

 Pteromalus amoenns Forster, 1841 : 28, " £ " [rede $]. 

 Pachyneuron formosum Walker ; Thomson, 1878 : 28-29, 6* ?• 

 Pachyneuron formosum Walker ; Delucchi, 19556 : 128, 133, o* $. 



Type material. Pachyneuron formosum Walker. Syntypes, 7 specimens. 

 LECTOTYPE, the seventh in the series, a female, bearing a Waterhouse label. 



Pteromalus incubator Forster and P. amoenus Forster. Type material in 

 Naturhistorisches Museum, Vienna (coll. Forster). I have not seen the types of 

 these species, which were placed in synonymy with Pachyneuron formosum by 

 Delucchi (19556 : 133) ; this author stated (ibid. : 124) that Forster's type of 

 amoenus (described as a male) is really a female. 



Boucek (1965^ : 18) has suggested that Pachyneuron umbratum Delucchi may be 

 the same as formosum Walker. I find some small though apparently constant 

 differences between the two, and regard umbratum as a valid species (for additional 

 details, see umbratum). 



Britain, France, Germany, Italy. 



Biology. P. formosum has been recorded as a parasite of Syrphus ribesii L. in 

 Germany and of Xanthandrus comtus (Harr.) in Italy (Secretariat, etc., 1963 : 343, 

 368) ; also of Epistrophe [=Syrphus~] balteata (DeG.) in France (Ibid., 1966 : 120, 

 130). These records, based on specimens determined by Dr. Delucchi, are accepted 

 as correct. I have seen the specimens to which Delucchi (19556 : 133) refers, 

 reared from a " Syrphus " on cabbage at Levallois-Perret, near Paris ; they are 

 typical formosum. Delucchi's earlier record (1954 : 246) of formosum as a parasite 

 of Syrphus arcuatus Fin. was later stated (Delucchi, 19556 : 133) to refer to grande 

 Thomson and not to formosum. Imagines appear (in Britain) Aug.-Nov. 



Pachyneuron grande Thomson 

 (Text-fig. 680) 



Pachyneuron grande Thomson, 1878 : 29, $. 



Pachyneuron grande Thomson ; Delucchi, 19556 : 128, 133-134, o* $. 



Type material. Syntypes, 2 $. LECTOTYPE, a female labelled " Die Bhn " 

 [Dalecarlia, Boheman] and " grande Ths ". 



Delucchi (19556) has given a good redescription of grande. Most of the 

 characters he describes hold good for all the specimens I have seen. The range of 

 variation in size, however, is rather greater than he states ; females vary in length 

 from 1 -8 to 3 mm. He says (19556 : 128) " Funiculusglieder beim Weibchen immer 

 langlich " ; but although the majority of females have the proximal segments of the 

 funicle slightly longer than broad, the distal segments are usually quadrate, whilst 

 in one exceptionally small specimen all the segments are quadrate. 



Sweden, France, Switzerland, Czechoslovakia, Moldavian S.S.R. 



Biology. Reared in Switzerland from puparia of Syrphus arcuatus Fin. (Delucchi, 

 19556 : 134) ; recorded as a parasite of Epistrophe [= Episyrphus] balteata (DeG.) 

 in France (Secretariat, etc. 1966 : 120, 130). Imagines July-Sept. 



