810 M. W. R. de V. GRAHAM 



tion kindly supplied by Dr. Novitzky, who saw the types, vesparum is a valid species 

 of Dibrachys. Dr. Boucek recently sent me both sexes of a Dibrachys which might 

 be the true vesparum, reared in Germany (Eschbach, 2.U.1966, R. Gauss) from a 

 nest of Dolichovespula saxonica (F.) (Hym., Vespoidea). It differs from all the 

 species included in my key above. At this late stage I cannot modify my key, and 

 prefer in any case to leave to Dr. Boucek the decision whether the species is vesparum 

 or not. 



Dibrachys (Dibrachys) lignicola sp. n. 



In addition to the characters given in my key (which are considered diagnostic), 

 lignicola has also the following: 



$. Antennal scape testaceous, or more or less infuscate distally ; head and thorax olive or 

 bronzy olive greenish dorsally, dark blue ventrally ; legs, apart from the coxae, testaceous with 

 the hind femora usually, the fore and mid femora sometimes, more or less infuscate ; rarely 

 some or all of the tibiae (e.g., in Irish $$) are brownish medially. Tegulae brown. Head in 

 dorsal view (Text-fig. 668) about 1-9 times as broad as long, with temples slightly angulate 

 posteriorly ; ocelli in a very low triangle (about i22°-i25°) ; mandibles moderate-sized, their 

 lower margin hardly sinuate or margined. Scutellum not strongly convex, less so than in 

 cavus. Plicae of propodeum distinctly curved, converging posteriorly. 



o*. Colour as $, but gaster with a subbasal testaceous spot ; flagellum brown or brownish 

 testaceous. Antennal scape (Text-fig. 663) with a small projection at its upper internal angle, 

 the antenna otherwise much as in $ cavus (Text-fig. 665). 



Holotype $. Ireland : Co. Dublin, Harold's Cross, 22.viii.1954, on a wooden 

 post in garden at 14, Clareville Road {Graham), in Hope Department, University 

 Museum, Oxford. 



Paratypes. England : Berkshire, Wytham, $$, 10.viii.1952, 17.viii.1952 

 {Graham). Ireland : Co. Dublin, Harold's Cross, 1 $, 14.vi.1937, 1 $, 15.vi.1937, 

 1 $, 27.ix.1937, 1 $, 17.vi.1941 (Stelfox) ; 1 $, 21.viii.1954, several $$, 1 $, same 

 data as holotype. Paratypes in Stelfox and Graham collections. 



Biology. Unknown. 



Dibrachys (Dibrachys) cavus (Walker) 

 (Text-figs. 659, 664, 670) 



? Diplolepis microgastri Bouche, 1834 : 168, q* $. 



Pteromalus cavus Walker, 1835 : 477, $, [?] q\ 



Pteromalus decedens Walker, 1835 : 478, <$ $, syn. n. 



? Pteromalus perversus Walker, 1835 : 479, " $ " [recte <$]. 



Pteromalus tenuis Ratzeburg, 1844a : 195, <J. 



Pteromalus Bouchdanus Ratzeburg, 1844a : 196, $. 



Dibrachys Boucheanus (Ratzeburg) Thomson, 1878 : 161, o* ?■ 



Dibrachys cavus (Walker) Kurdjumov, 1913 : 11. 



Dibrachys cavus (Walker) ; Muesebeck et al., 1951 : 553-554. 



Dibrachys cavus (Walker) ; Peck, 1963 : 674-682. 



Dibrachys cavus (Walker) s. lat. ; Boucek, 19650 : 30. 



The literature on cavus (Walker) is very extensive ; for very useful summaries 



