70 BRITISH ICHNEUMONS. [ Stenomacrus 

laterally impressed beyond the centre and at least in @ distinctly 
bicarinate; anus of @ distinctly compressed, with terebra not exserted. 
Legs stout and fulvous, of ¢ long with the anterior entirely stramineous 
and hind ones flavescent; claws and pulvilli not large; calcaria curved. 
Wings hyaline with radial nervure apically straight; areolet distinct and 
subpentagonal with the outer nervure pellucid; radix and tegulae of ¢ 
flavous, of @ piceous; stigma in both sexes extremely pale stramineous 
and much paler than the nervures; anal nervure emitted from centre of 
brachial cell. Length, 3—4 mm. 
At once known by the peculiarly pale stigma, which resembles only that 
of S. flaviceps and S. caudatus, the profuse pale markings of the g, which 
differs from that of .S. cawda/us in its entirely pale pronotum and stouter 
outline, and the conspicuously binotated 9 frontal orbits. 
This is certainly one of the most abundant species in Britain, though 
the synonymy is too involved to determine its Continental range; | 
possess seventy specimens. The male appears to be restricted 1n its 
duration of perfect existence to a short period, since it has occurred to me 
abundantly in Tuddenham Fen, at Foxhall, on Pinus sylvestris in Bentley 
Woods, Bramford and on Pine at Brandon ; | have repeatedly taken it on 
fir trees near Elvedon in Suffolk and on r4th June, 1902, it was excessively 
common there among bracken, sitting on the trunks and flying to the 
branches of these trees, from which I beat both sexes on oth of the follow- 
ing June. Though undoubtedly attached to Conzferae, among which the 
type was commonly captured by Haliday at Holywood, it also occurs on 
oak and sallow, whence I took numerous examples at Mousehold Heath, 
near Norwich on 9th June, 1901, and Bridgman also found it there on 
ling in July ; near Ipswich it occurs on birch, at Barton Mills on poplar 
and at Southwold on reeds. ‘The male is very rare in May and I have not 
seen it later than 22nd June; but the female has a much longer span, my 
dates ranging from 3rd July to 28th September at Tuddenham on birch, 
Foxhall on the flowers of Sfrraea ulmarva and at Oxshott in Surrey. 
Piffard has found it at Felden in Herts, Butler at Abinger Hammer, Mar- 
shall at Darenth Wood, Yerbury at Oxshott early in June, and Wilson 
Saunders at Reigate in Surrey, Tuck at Finborough in Suffolk and 
Beaumont at Chobham, and Blackheath in Kent. No host has yet been 
assigned to it. 
8. ridibundus, Grav. 
Orthocentrus ridibundus, Gr. I. E. iii. 366, ¢; Holmgr. Sv. Ak. Handl. 1855, 
p. 337,  ¢. Stenomacrus ridibundus, Thoms. O. E. xxii, 2437, ¢ ¢. 
A punctulate, somewhat shining and large species. Head _ transverse 
and not buccate; frons a little impressed in front; face punctulate and 
somewhat protuberant; mouth and in g whole, or in @ part, of face 
flavous. Antennae filiform, a little shorter than the body, with the three 
basal joints luteous or in @ paler beneath; basal flagellar joint cylindrical 
and as long as the following. Thorax stout, gibbulous and discally punc- 
tate, ¢ often with a prothoracic mark ferrugineous; metathoracic areae 
obsolete, areola wanting though basally indicated, petiolar area distinct. 
Abdomen sublinear and subsessile, as long as the head and thorax and in 
6 narrower than the latter; first segment deeply sulcate and basally sub- 
constricted, twice longer than broad in g, in Q shorter; second trans- 
versely impressed, of g quadrate and of ? transverse; two basal segments 
