Odoii/omcnis.'] BRITISH ICHNEUMONS 11 



A black, punctate and shining species. Head with the palpi pale or 



iiifuscate ; labruni sometimes red or dull ferrugineous. Antennae longer 

 than half the body, subsetaceous, black. Thorax immaculate ; mesonotum 

 punctate ; metathoracic apophyses distinct and subacute. Abdomen as 

 broad as and a little longer than the head and thorax, black or nigre- 

 scent, rarely piceous and usually with the central segments sub-badious ; 

 basal segment straight, one third the length of the abdomen, generally 

 apically paler, of (J long, linear and aciculate, of 9 shorter and strongly 

 dilated apically, smooth or scabrous with the spiracles before its centre ; 

 terebra emitted before anus and as long as the body, black with spicula 

 red. Legs normal, red ; femora somewhat compressed, the hind ones 

 stouter and elongate-oval with a strong and apically subreflexed tooth be- 

 neath, between which and the base they are finely ciliate and sometimes 

 infuscate ; coxae and trochanters nigrescent with the apices of the latter 

 red ; intermediate tibiae of 9 curved before the apex ; hind tarsi often 

 infuscate. Wings somewhat clouded with stigma infuscate or piceous, 

 radix and tegulac stramineous, the former sometimes ferrugineous and 

 the latter often black. Length, 5-14 mm. 



Each host, probably, has a slightly different form of this parasite. 



Thomson (O.K. viii, 777) has broken this species up into three, 

 O. Pinctonim, melanarius and punctidatus, founded mainly on the \-ar3'ing 

 length of the terebra. I am, however, convinced that these are but forms 

 of one, since specimens bred together show very distinct variability in 

 this respect. Gravenhorst's very full description and initial diagnosis 

 distinctly show that it is the last of these " forms " which he describes. 



The widely distributed Continental O. appoidiciila/its, Grav,, differs in 

 the narrower basal segment which is apically appendiculate on either side, 

 the laterally more strongly punctate head and the much longer terebra. 

 Following the above useless method of comminuting this present species 

 into several, O. appaidicidatus and Thomson's new O. qiiercinus (which 

 differs from it in having the terebra only as long as the body), are the 

 only species with the intermediate tibiae simple. In early June, 1907, 

 Mr. Keys was so good as to send me many O. dcntipcs bred by him from 

 Rhopalomesites iardyi at Plymouth ; these have the tibiae simple and 

 terebra as long as the body, but every other character of that species is 

 utterly lacking, conclusively showing them to be inconstant. 



This is by no means an uncommon species on the Continent, where 

 Ratzeburg thought it might possibl}' be parasitic upon Bomhyx monacha ; 

 Dours (Cat. 72) probably erroneously adds Osmia aurulcnta and O.bicolor; 

 but Gravenhorst, who also found it in August, once noticed a female 

 flying about a stack of wood at Breslau, in June, and its relationship to 

 lignivorous Coleoptera is strongly presumptive from a MS. note in 

 Marshall's copy of his 1872 Catalogue: " $ taken by liignell, Aug. 6th, 

 entering burrows of Mcsiles tardii'' {cf. Trans. Ent. Soc, 1907, p. 57). 

 This is the only mention I can find of its occurence in Britain, where it 

 was first introduced in 1870. In May, 1907, Donisthorpe discovered in 

 London, a live $ in a drawer of his insect-cabinet, where were specimens 

 of the above weevil recently taken near Plymouth ; on hearing of this, I 

 requested Keys to procure specimens from that locality, which he did, the 

 largest measuring only 6 mm. So small a host naturally causes a relatively 

 small parasite ; whereas a female taken at Newtownmorc, by Donisthorpe, 

 in 1907, is nearly 12 mm. in length, of the ioxm pineionitn in pedal colour 

 2lx\A punctulaliis in terebral length. 



