194 BRITISH ICHNEUMONS. \Pezomachus. 



Abdomen diffusely punctured and pubescent, shining ; first segment with 

 slightly projecting spiracles. Legs stout. 



Head deep black ; antennae red to middle, thence gradually darker to 

 the black-brown apex. Thorax red. Abdomen with segments one to 

 four red, the rest black, with narrow red posterior margins. Legs red, 

 exactly same colour as thorax and basal segments of abdomen ; hind 

 femora at apex, the middle and hind tibiae, and last tarsal joint brown. 

 Length, 2-3 mm. 



This species receives its name from the longitudinal furrow on thorax, 

 which is most distinct on the metanotum, but Fdrster says that in one of 

 his specimens this furrow was absent ! This feature reminds one of the 

 Stilpnini rather than the present genus, but the absence of all mention of 

 shape or outline precludes further classification. 



It was first recorded from Britain by Marshall in his 1872 Catalogue, 

 but I have heard of no captures having been effected since that time, and 

 the species must be regarded as doubtfully indigenous. 



12. pilosus, Capro7i. 

 Pezoj/iackus pilosus, Capron, E.M.M. 1888, p. 217, 9. 



Head broader than thorax ; antennae very stout and sub-attenuate at 

 base and apex ; basal flagellar joint shorter than the second ; fifth sub- 

 transverse. Metathoracic transverse costa centrally wanting, though 

 laterally distinct ; petiolar area smooth and somewhat excavate centrally ; 

 thorax clothed with elongate bristly hairs. Abdomen somewhat nitidulous, 

 with diffuse long erect hairs, between which the surface is finely reticulate ; 

 basal segment somewhat long and gradually explanate apically, with pro- 

 minent spiracles between the centre and apical third ; terebra slightly 

 shorter than the basal segment. 



Head dull black ; antennae with the four basal flagellar joints fulvous. 

 Prothorax sometimes entirely black ; mesonotum pitchy red, with a black 

 spot on the disc ; metathorax red, often with the sides and petiolar area 

 black. Abdomen piceous black, with the basal segment, except a central 

 discal line, red. Legs red. Length, 5-6 mm. 



This species is easily recognized by the bristly hairs which clothe the 

 thorax and abdomen. Three specimens were originally taken by Dr. 

 Capron in 1887, at Shere in Surrey ; these are now in my collection. It 

 has since been found by Beaumont at Appledore in Kent, in September 

 and October, 1900. I possess two females captured by Piffard at Felden 

 in Herts. ; in these the abdomen is unusually coarsely and distinctly 

 punctate. Chitty has taken the same form at Huntingfield in June, 1905. 



13. acarorum, Linn. 



Mutilla acarorum, Linn. S. N. ii. 968 (tiec Schr.). Pezovmchus acaroni»i, Thoms. 

 O. E. X. 1017, $ 9 (>iec Grav.). P. hortensis, Gr. I. E. ii. 907 (part), excl. 9 ; r/ i. 

 Suppl. 717, (J. P. xylochophilus, Forst. Wiegm. Arch. 1850, p. 169, 9. P- avidus, 

 Forst. lib. cit. 1851, p. 33, 6- 



Cheeks buccate, with the sulcus indistinct and costa inflexed ; man- 

 dibles tuberculate basally ; clypeus broadly truncate-marginate at apex. 

 Antennae short and stout ; basal flagellar joint hardly longer than the 



