94 M. W. R. de V. GRAHAM 



Panstenon oxylus (Walker) 

 (Text-fig. 55) 



? Pteromalus assimilis Nees, 1834 : 116-117, $. 

 Miscogaster Oxylus Walker, 1839 : 196, <$ 9. 

 Pteromalus omissus Forster, 1841 : 30, $. 

 Panstenon oxylus Walker, 1846 : 29. 

 Panstenon Pidius Walker, 1850 : 132, <$, syn. n. 

 Panstenon oxylus (Walker) ; Reinhard, 1858 : 17. 

 Panstenon assimilis (Nees) Thomson, 1878 : 176-177, <$ $. 

 Panstenon oxylus (Walker) ; v. Rosen, 1956 : 1-72 {passim). 

 Panstenon oxylus (Walker) ; Kerrich & Graham, 1957 : 2 &°- 

 Panstenon oxylus (Walker) ; Ferriere & Kerrich, 1958 : 26. 

 Panstenon assimilis (Nees) ; Boucek, 1961 : 72. 



Type material. Pteromalus assimilis Nees. Type lost. Thomson (1878) con- 

 sidered it apparently the same as oxylus, and Boucek accepted this synonymy. 

 Nees' description of assimilis (" nigro-aeneus . . . metathorace laevi, nitido, tri- 

 carinato . . . ") leaves some doubt, however. 



Miscogaster oxylus Walker. There are 4 Walker specimens in the BM(NH) but 

 only two (in the British collection) can be considered syntypes ; they are 2 <$. 

 One of these is designated LECTOTYPE ; it is card-pointed (remounted) and bears 

 a Waterhouse label " Panstenon Oxylus Walker ". 



Pteromalus omissus Forster. Type $ presumably in Naturhistorisches Museum, 

 Vienna. Reinhard (1858 : 17) synonymized it with oxylus. The original descrip- 

 tion of omissus certainly suggests that it is identical with oxylus. 



Panstenon pidius Walker. In Haliday's collection there are two males having 

 narrow wings ; both are presumably syntypes of pidius. One (Hal. coll. no. 100) 

 is designated LECTOTYPE ; it is mounted on a card, and the pin which carries 

 it has its head coated with green sealing-wax (one of Haliday's methods of indicating 

 Irish origin) ; it bears a label in Walker's handwriting " Panstenon Pidius ". The 

 lectotype has very narrow wings. The wings in oxylus vary considerably in their 

 proportions (especially in males) and I have intergrades between the typical form 

 and the form pidius. The body in the forms with narrow wings is sometimes more 

 slender than usual, and in the most extreme specimens appears slightly deformed. 

 These variations are probably caused by pressure during the development of the 

 pupa. 



Britain, Ireland, Denmark, Sweden, Finland, Germany, Austria, Central 

 Europe. 



Biology. See von Rosen (1956 : 1-72, passim). This author states that the 

 larva of oxylus lives as a predator on the eggs of Javesella (= Delphacodes) pellucida 

 (F.) (Hem., Delphacidae) in the internodes of various grasses ; he figures the egg, 

 larva, and adult, and summarizes the life-history on p. 65 of the above paper. 

 Walker (1850 : 132) recorded "Panstenon Oxylus, reared by Mr. Haliday from the 

 pupa of a Dipterous insect (Agromyza pisi, Kaltenbach) on the pea ". In Haliday's 

 collection there is a female of oxylus, labelled as such, mounted upon a card on which 



