Plecliscus'] BRITISH ICHNEUMONS. 11 



more obviously constricted basal third of the hind tibiae and the usually 

 basally scrobiculate petiole. This species is distinguished from P. coUaris, 

 to which it is similar though smaller, in the more slender antennae and 

 legs, basally infuscate-ferrugineous hind coxae, narrower vertex and 

 distinct j)ctiolar scrobes. The male differs only sexually. 



It has hitherto been recognised only from Aix and northern Germany; 

 but 1 possess a specimen, certainly correctly named by Dr. Sigisumnd 

 Brauns, which Alfred Beaumont captured on 27th July, 1898, at Chobham 

 in Surrey. I took a female on the window of Plonk's Soham House, 

 Suffolk, on 30th August, 1907, and both sexes are well represented from 

 Shere in Capron's collection. 



6. melanocerus, Forst. 



PlcctiscHs melanocerus, Forst. Verb. pr. Rheinl. 1871, p. 87, ?. Var. P. 

 sodalis, Forst. lib. cit. p. 88, ? ; Thorns. O.K. xii. 1303, <? ? . 



A black species w ith the antennae slightly beneath and the legs pale, 

 the hind coxae towards their base black, with the petiole apically deplan- 

 ate and substriate on either side. Stigma somewhat narrow, emitting 

 radial nervure from its centre ; petiolar spiracles not prominent; antennae 

 i6-jointcd; terebra not longer than the two ba.sal segments. Length, 

 3-4 mm. 



The var. sodalis, hitherto regarded as the typical form, thougli ante- 

 paginated, has 2 1 -jointed antennae, with the clypeus and antennal base 

 distinctly pale; other forms differ in having 20- to 23-jointed antennae. 



The typical form was captured in Prussia, and does not seem to have 

 been taken elsewhere. Indeed, our own claim to it rests solely upon its 

 record from Buckenham in the Norfolk Broads by Bridgman, and even 

 this is queried, doubtless on account of Forster's inadequate description. 



7. communis, Forst. 



Plcctisciis communis, Forst. Verli. pr. Ivhciiil. 1871, pp. S(S ct 91 ; Thorns. O.K. 

 .xii. 1299. cT ? . 



A slender, black, piceous or testaceous species of variable colour. 

 Head with the vertex broad and posteriorly ruundly constricted; cheeks 

 elongate and clypeus superficially discreted. Antennae somewhat stout 

 and basally flavidous, with the ilagellar joints distinct and in S the sixth 

 and seventh subemarginate. Thoracic notauli almost wanting. Abdomen 

 centrally flavidous; first segment ba.sally bicarinate; terebra almost as 

 long as whole body. Legs distinctly stout and flavidous. Wings with 

 nervellus vertical and not geniculate. Length, 3-4 mm. 



Thomson says it is distinct in its obsolete notauli, not very slender 

 antennae and legs, entire and vertical nervellus, somewhat broad and 

 posteriorly roundly narrowed vertex, strongly elongate terebra and basally 

 bicarinate petiole. 



It has been found at Aix-Ia-Chapelle (Liirster), Ringsjon in Sweden 

 (Thomson), northern France (Lethierry) and is not rare in Thuringia 

 (Schm.). It has not hillierto been noticed in Britain, whence is an 

 example in the Edinburgh Museum, which I have no liesitation in assign- 

 ing to the present specits. I also possess three females from Surrey and 

 1 krll'urdsiiirL' in Capron's and I'iffard's collections. 



