Ifeiniie/es.] BRITISH ICHNEUMONS. 15I 



usually stramineous ; V clyiieus discretcd and apically sub-rcflexed. 

 Antennae sub-tiliform and shorter than tlie body. Tliorax with the meso- 

 notum coriaceous-rugose ; mctathorax short with complete areae and 

 strong costae ; areola narrow ; petiolar area sub-discreted. Abdomen 

 oblong-ovate, deplanate, finely alutaceous and confluently punctate with 

 the apices of the basal segments sub-callose and nitidulous ; of S slightly 

 narrower, of $ rather broader, than the thorax, sub-petiolate ; of S black, 

 of $ with segments two to four and a[)ex of the first rosy or castaneous ; 

 basal segment short and broad, strongly convex, gradually dilated a[)ically 

 and hardly twice longer than broad ; post-petiole broad, as long as the 

 petiole, of ^ sub-quadrate, of 9 transverse ; terebra rather longer than 

 half abdomen, red with valvulae black and gradually incrassate apically. 

 Legs red ; coxae and trochanters, except apices of latter, black ; femora 

 sometimes entirely black, usually with apices or base, and occasionally 

 the anterior pairs mainly, red ; tibiae except basally and apically 

 red, rarely entirely black ; hind tarsi infuscate. Wings normal, of $ 

 somewhat distinctly clouded ; tegulae and the narrow stigma infus- 

 cate, radix stramineous ; areolet externally usually obsolete. Length, 

 4-5 mm. 



Gravenhorst says the S is similar to H. tristator, but with the basal 

 segment shorter and broader ; the $ resembles H. ridibi/ndits, but its 

 abdomen, especially the petiole, is shorter and broader, with the thorax 

 less gibbous and the antennae longer and more slender. The distinct meta- 

 thoracic lateral costae and ? clouded wings will distinguish it from both 

 H. floricolator and melanogaster. And from all our indigenous species the 

 triangular head, rugosely coriaceous frons and mesonotum, clouded wings 

 which have the basal nervure a little oblique, very finely striolate and 

 transverse post-petiole, and the acute epipleurae of segments two to four 

 will render it distinct. 



This species is gregarious and usually, though not always, hyperparasitic ; 

 as many as eighteen specimens have been bred from a single host, whose 

 chrysalis was filled with their thin, brown, honeycomb-like cocoons, with 

 no trace of an intermediate parasite. Curtis first associated the sexes in 

 i860 and figured the female (reproduced in Ormerod's Guide, p. 122); 

 he bred " an incredible number," considering their size, of males and 

 females of this species in July or August from a single largish hole in the 

 side of a pupa of Pieris napi. 



It is a common parasite upon Pieris brassicae and economically a most 

 beneficial insect. It is said to occur in June, September and October 

 upon shrubs and umbelliferous flowers throughout Europe. Taschenberg 

 bred both .sexes from the above host in Germany and Laboulbene in 

 France ; in Devon, Bignell has raised it from Pieris rapae : and Bridgman 

 tells us two males and sixteen females emerged from a single New Forest 

 pupa o{ Argynnis paphia, on 8th July, 1882. It has also been bred from 

 Coleophora Giraudi, Rag., by Giraud ; both sexes from Vanessa C-albiim, 

 by Holmgren ; Psyche sp., Solenobia lri(jueirella^ Pissodes notatus^ Jlylurgus 

 piniperda and from spiders' eggs (Bridg.-Fitch). It is said to be abundant 

 at Glanvilles Wootton by Dale, and is recorded from Guernsey by Luff; 

 there are two females in Dr. Capron's collection from Shere, and both 

 Miss Chawner and I have taken it in the New Forest, in August. 



