Trichomast:x ] BRITISH ICHNEUMONS. 127 

wanting; fenestrae large and entire, nervelet indicated ; nervellus sub- 
opposite and intercepted distinctly below the centre. 
This very distinct genus—ausgezeichnete Gattung, as Thomson terms 
it—is at once recognised by the large and pale metathoracic spiracles and 
the transcostate scutellar fovea; in the strongly compressed ? abdomen 
it is allied to Phthorimus. 
Only one species is known. 
1. flavipes, Holmgr. 
Bassus flavipes, Holmgr. Sv. Ak. Handl. 1855, p. 356, ¢; Trichomastix palli- 
pes (sic), Thoms. O. E. xiv. 1473, ¢ 9. T. polita, Voll. Tijds. v. Ent. 1878, p. 161, 
pl. ix, f.4,?. Bassus tibialis, Bridg. Trans. Ent. Soc. 1883, p.170,%. Tricho- 
mastix flavipes, Morl. lib. cit. 1905, p. 425, 3 ?. 
A very strongly nitidulous black species with only the metathorax and 
basal, or in ¢ two basal, segments rugulose. Metanotum subglabrous. 
Mouth, clypeus and in ¢ the face centrally and laterally to the scrobes, a 
dot beneath and line before the concolorous tegulae, the sides of the scu- 
tellum somewhat broadly at least basally, the metathoracic spiracles and 
sometimes apex of the frenum, flavous. Legs fulvous throughout with 
only the base of the tibiae and tarsi indeterminately whitish ; hind tibiae 
rarely subinfuscate. Abdomen of @ normal, broader than high and sub- 
cylindrical ; of @ very strongly compressed from the base of the third 
segment and often elongately protruded; terebra shortly exserted. 
Length 7—g or (if protruded) 11 mm. 
My two 9 9 are practically of the same size; but, while one has the 
abdomen 4 mm. in length and apparently in its normal state, the other 
has it protruded to a length of 8 mm. or two-thirds that of the whole 
insect. 
Boheman first found the ¢ rarely in Sweden, Kriechbaumer took a @ 
in Silesia, Thomson says it has been bred from a Syrphus pupa in 
Denmark, and van Vollenhoven describes a 9 from the sea-dunes at Sche- 
veningen, near the Hague, whence van Burgst in 1911 records a female. 
M. A. Roman told me in 1906 that this species is not found at Upsala, but 
that near Stockholm he once discovered the males swarming, with but a 
single female, on the juice of an old oak. Bridgman possessed three 
British females, two of which were bred by J. E. Fletcher from the pupae 
of some Dipferon dug up at Worcester on 22nd Mav, 1872, and the third 
was captured by Norgate, probably (Trans. Norf. Soc. v. p. 629), in Nor- 
folk. 1 possess a male in Dr. Capron’s collection, probably taken at 
Shere, in Surrey; and Bignell has kindly given me two of the four 
females captured by him on 17th June, 1889 (E. M. M. 1908, p. 136) at 
sap caused to flow from an old oak tree by the action of larvae of Cussus 
ligniperda in the Walkham Valley, near Grenofen Bridge. 
