122 M. W. R. de V. GRAHAM 



mesoscutum blue, almost always with a violet discal spot ; spiracular areas of propodeum 

 more or less violet or purplish ; scutellum more regularly sculptured, with the striations more 

 extensive. 



Holotype <$. Ireland : Co. Wicklow, The Glen of the Downs, 23.viii.1954 

 {Graham), in Graham collection. 



Paratypes. England : Oxfordshire, Otmoor, 1 $, 2.VL1956, 1 $, 6.viii.i956 

 {Graham) ; Ireland : North Kerry, Headley Bridge, 1 <$, 28. vi. 1934 {A. W. Stelfox), 

 in Graham collection. Unlocalized, but probably Ireland : 1 <$ in Haliday collec- 

 tion (No. 874). 



Biology. Unknown. 



Platygerrhus tarrha (Walker) comb. n. 



Trigonoderus Tarrha Walker, 1848 : 128, 217,0". 

 Trigonoderus tarrha Walker ; Kerrich & Graham, 1957 : 299. 



Type material. Listed by Kerrich & Graham (1957 : 299) as a doubtful species. 

 The single male standing under this name is now designated LECTOTYPE ; it is 

 represented only by the antennae, wings, and parts of the legs. From these 

 remains it is clearly a Platygerrhus, whilst the antennae are distinctive and agree 

 exactly with those of a recently caught male in my collection. Hence I feel confident 

 that I can identify the lectotype, which represents a valid species. So far I have not 

 been able to associate any females with this male. 



Britain : " England " (Walker, 1848 : 128) ; Oxfordshire, Otmoor, 1 <$, 29.viii 

 1956 {Graham). 



Biology. Unknown. 



GASTRACANTHUS Westwood 



Gastr acanthus Westwood, 1833 : 121. Type-species : G. pulcherrimus Westwood, by monotypy. 



Hetroxys Westwood, 1833c : 495 [n. n. for Gastr acanthus, supposedly pre-occupied] . 



Photismus Thomson, 1878 : 4, 15. 



Photismus Thomson ; Schmiedeknecht, 1909 : 156, 157, 165-166. 



Photismus Thomson ; Nikol'skaya, 1952 : 212. 



Gastr acanthus Westwood 

 Gastracanthus Westwood 

 Gastracanthus Westwood 

 Gastracanthus Westwood 



Kerrich & Graham, 1957 : 281-284. 

 Ferriere & Kerrich, 1958 : 24-25, 29. 

 Kamijo, 1960a : 102-106. 

 Peck et al., 1964 : 35. 



Gastracanthus was misinterpreted until Kerrich & Graham (1957) recognized its 

 true position. Hetroxys Westwood had earlier been wrongly identified by Thomson 

 (1878 : 48, 86, as " Etroxys ") as a Pteromaline genus. 



Photismus Thomson was placed in synonymy with Gastracanthus by Kerrich & 

 Graham (1957 : 281). 



The genus is widely distributed in the northern hemisphere ; one species is known 

 in Europe, others in North America (see Kerrich & Graham, 1957 : 283) and in 

 Japan (Kamijo, 1960a : 102-106). 



