166 BRITISH ICHNEUMONS. [ Mesolerus 

third longer than apically broad, with its basal fovea apically open and 
continued bicarinately to beyond centre of postpetiole ; anus subnitidu- 
lous. Legs not slender, red with only the hind tibiae and their tarsi 
entirely black. Wings with no areolet; nervellus antefurcal and inter- 
cepted below centre. Length, 6 mm. 
In the facies of size and shape it is said to resemble Lrromenus frenator, 
but with more slender legs. Superficially similar to JZ. haematodes but 
shorter and stouter, with the abdomen of 9 much more convex. 
Bridgman bred a single pair from larvae of the pear-tree saw-fly, Erio- 
campa caninae, found ina Norwich garden. ‘The same author records 
(Trans. Norfolk Naturalists’ Soc. 1894, p. 626) two more of his own 
species, AZesolevus pedatus, Bridg., and MV. calcaratus, Bridg., from Brundall 
near Norwich: these are MS. names. I took a female of this species, 
peculiar for its short, squat conformation in a greenhouse of a garden at 
Ryde, in the Isle of Wight on 17th August, 1903. It is not yet known 
elsewhere. 
36. filicornis, Holmgr. 
Mesoleius filicornis, Holmgr. Sv. Ak. Handl. 1876, p.40; Thoms. O. E. xix. 
2068, ¢ 2. (?) Bassus athaliaeperda, Curt. Farm Ins. 1860, 53, ¢?. 
Head posteriorly a little constricted; cheeks not buccate; clypeus api- 
cally depressed and truncate; mouth, clypeus and most of @ face 
stramineous. Antennae with flagellum apically ferrugineous beneath. 
Thorax short, subelevated and stout in front, with a dot or mark before 
radices stramineous and very determinate notauli extending to apex; 
mesopleurae alutaceously punctate and in ¢ subglabrous above; areola dis- 
tinct, petiolar area with a very distinct in g and obsolete in 9? central 
carinula. Abdomen with the central incisures of ¢@, rarely broadly, dull 
red; basal segment not narrow, about length of hind coxae, with basal 
fovea apically open and carinulae extending beyond spiracles; second 
nearly half as broad again as long with distinct thyridii; third transverse 
and shining, following becoming gradually smoother, with terebra short. 
Legs pale red with the normally stout hind tarsi and their tibiae black, 
the latter basally broadly white-banded. Wings with stigma dull 
stramineous, radix and tegulae white; areolet wanting; nervellus ante- 
furcal. Length, 6 mm. 
Thomson says the base of clypeus and centre of ¢ face are black, he 
also introduces a white pronotal callosity in both sexes; he considers 
this species distinct in its black scutellum and venter which is only white- 
margined, and in the colouration of the clypeus and ¢ face. 
It is impossible to tell what Curtis’ “‘ Bassus” was, but I think the in- 
adequate description leaves but little doubt that it belongs to the present 
genus, wherein there are points of analogy with JZ. filicornis. Bassus does 
not prey upon saw-flies, and Curtis bred his insects in England from the 
destructive “‘ Black Jack,”’ A¢halia spinarum, Fab. 
The first intimation we have of this species, elsewhere only recorded 
from central Sweden, as British is Bridgman’s chatty statement (Trans. 
Norf. Soc. 1893, p. 63) that he took a couple of specimens on ling at 
Mousehold Heath near Norwich, and that he thought “it not improbable 
they were parasitic” on Zenthredo obsoleta ; at hd. cit, 1894, p. 625, he says 
he has also found this parasite at Eaton and Brundall, in Norfolk. It has 
