216 BRITISH ICHNEUMONS. [ Mesoleplus 

MESOLEPTUS, Gravenhorst. 
Gr. I. E. ii. (1829), 3; Holmgr. Sv. Ak. Hand]. 1855, p. 100. 
Head transverse and not buccate, vertex subemarginate; mandibles 
bidentate, with the lower tooth often the longer; clypeus subdiscreted, 
not convex, often apically depressed; face not prominent, nearly always 
flavous-marked. Antennae filiform, very slender and never shorter than 
body ; basal flagellar joint longer than second, scape ovate. Notauli 
generally distinct and mesonotal disc often deplanate; metathorax 
evenly rounded and at most longitudinally bicarinate centially; spiracles 
circular. Scutellum normal, subconvex. Abdomen distinctly petiolate 
and always more or less broadly red; basal segment sublinear, strongly 
elongate and subparallel-sided throughout, with spiracles at or near its 
centre; anus of 2 often compressed. Legs slender and elongate; hind 
tibiae bicalcarate, tarsal claws somewhat large and not pectinate. Wings 
ample and somewhat broad; areolet usually entire ; nervellus variable. 
This differs from all other Tryphonid genera in the structure of its 
basal segment, straight and not curved disco-ventrally, slender, narrow, 
very slightly explanate towards its apex and always parallel-sided to the 
spiracles, with the apical margin at most one-third as broad as its total 
length. Consequently I use this genus in the broader sense as set forth 
by Holmgren in 1855 ; Forster's names form natural enough groups, but 
in a section of such irregular neuration as the present the absence of 
areolet, position of nervellus, etc., are not generic features and, if this 
were so, their adoption would unnecessarily complicate the classification 
of our “ limited fauna.” 
Very little progress could be made in the synonymy or further know- 
ledge of the last twenty-eight British species of this genus, placed 
alphabetically by Marshall in his 1872 Catalogue, because not referred to 
by Holmgren, until the Gravenhorstian types were competently revised. 
This has very recently been done by Pfankuch (Zeits. Hym.-Dip. 1906-7) 
with the result that, so far from belonging to this genus, almost the 
majority are not Tryphoninae at all. Of J/. albolineatus, Grav. (I. E. i, 
Suppl. 691) describes a single individual of uncertain sex, found by Hope 
near Netley, which he thought possibly a form of JZ. qguadriannulatus ; 
Stephens adds (Illus. vii. 215) that it occurs near London in June; and 
Desy. (Cat. 32) regards it asa form of Coelichneumon moestus, Gr.; but 
Pfankuch tells us the type is lost, and the species is not now represented 
in Stephens’ collection. J/. aniilope will be found under Ca/oglypius. 
Grav. compares (I. E. i, Suppl. 683) his AZ, arridens with M. xanthostigma 
and records an individual of ambiguous sex from Hope at Netley; 
Stephens (Illus. vii. 221) ‘‘ Found it near London in June,” and _ there 
are two Luryprocii under this name in his collection. Jdesatraclodes pro- 
perator, Hal. (Ichn. Brit. ii. 257) is a synonym of JZ. (Callidiotes ) luridator, 
Grav., placed under Euryproctus by Marshall in 1872, which = both the 
M. coxator and the M. ventrator, erroneously given as a form of JZ. de- 
dusor in the 1872 Catalogue. The typical form of JZ. delusoris a Catoglyp- 
tus. ML. decipiens, Gr. (I. E. ii. 16 ef ii. 848) is nothing but the 9 of 
Dicaelotus decipiens. M. evanialis, Gr. (I. E. ii. 16 ef Ste. Illus. vii. 213) 
from Darenth Wood in June, isa Campoplegid, Dimophora cognata, Brisch.; 
and that JZ. infernalis, Grav. ef Steph., belongs to the same Ophionid 
group is evidenced by the six Lashrop/ex in the latter’s collection, “ found 
