224 BRITISH ICHNEUMONS. {^Pezomachus. 



43. corrupter, Forst. 



Pezoiiiaclius corriiptor, Fdrst Wiegm. Arch. 1850, p. 150 ; Thorns. O. E. x. 1016, 9- 

 P. iusidiosHS, Forst. Wiegm. Arch. 1S51, p. 44, $. P. dyaalotiis, Forst. ///'. cit. 1851, 

 p. 61, i. Var. /'. fatiiiiis, Forst. ///'. <//. 1850, p. 165, 9 ; ^^- conveniens, Fcirst. ///'. 

 cit. 1851, p. 57, i ; P. diihitator, Ftirst. lib. cit. 1850, p. 191, ?. 



9 . Head with tlie genal sulcus I)ut slightly impressed, its costa in- 

 flexed ; mandibles more or less basally tuberculate ; clypeus sub-rotundate 

 and not raised apically. Antennae short and stout, with the basal flagellar 

 joint slightly longer than the second and the fifth longer than broad. 

 Mesothorax not transverse and shorter than the metathorax ; petiolar area 

 basally costate throughout ; acetabula occupying the greater part of the 

 mesosternum ; petiolar area oblique. Abdomen somewhat shining, finely 

 and somewhat closely pubescent on the three basal segments, more 

 diffusely apically ; basal segment gradually and equally ex[)lanate through- 

 out, with inconspicuous spiracles, those of the second far from the lateral 

 margins ; terebra as long as, or slightly shorter than, the first segment. 

 Legs stout with the anterior tibiae inflated and their coxae prolonged 

 almost to the base of the intermediate. 



Head black with the face more or less red centrally. Antennae fulvous, 

 slightly darker apically. Thorax and abdomen testaceous, the former sub- 

 piceous over the anterior co.xae, the latter with the anterior incisures and 

 apical segments often more or less piceous, as also is the terebra. Legs 

 fulvous, with the apical tarsal joint darker. 



$, . Apterous. Antennae with the two basal flagellar joints sub-equal, 

 the fifth twice longer than broad. Thorax with the petiolar area high and 

 its basal costa usually sharp throughout. Scutellum distinct. Abdomen 

 closely punctate and pubescent on three basal segments, more diffusely 

 apically ; spiracles of the first segment variable in size. 



Head black with the palpi flavescent and clypeus translucent red. 

 Thorax dull testaceous or darker laterally and around the scutellum. 

 Abdomen either with the two basal segments fulvous, the third darker 

 with or without a piceous discal mark, and the rest piceous or entirely red. 

 Legs immaculate testaceous. Length, 2^-5 mm. 



Thomson suggests that a form of the $ \% Hemimachits albipennis., Ratz., 

 but Marshall identifies this with Pezoinachiis avidits, Forst. So much 

 mystery at present surrounds this winged form that it is here omitted ; it 

 will, however, be noted that both authors allow the synonymy of Ratze- 

 burg's (J with an apterous form of the same sex, and it appears very 

 probable that this confusing dimorphism occurs in other species also. 



P. corruptor is similar to P. acaroniiii, Linn., but the terebra is longer, 

 the legs lighter, the mesonotum longer and the anus red-testaceous. This 

 species is certainly identical with P. faiiniis, from which it differs in 

 nothing but the colour of the abdomen, and even here the distinction 

 seems very slight. Forster says corruptor has fine lines on the second and 

 third segments, the fourth piceous and the fifth red, while faunus has no 

 brown lines, but the third to fifth are infuscate. The latter is distinguished 

 from P. xenoctonui in the shape of the slope and paler colour ; they are 

 probably not distinct. I have no doubt that P. dubitator is entirely 

 synonymous with the form y?j'//;i//jr, since the only discre[)ancy discoverable in 

 the descriptions is that the fifth flagellar joint is slightly longer in the former. 



The se.xes of this species were first bred together in Britain from Tale- 



