164 BRITISH ICHNEUMONS. [ Mesoletus 

sculptured at all above; areola and petiolar area finely costate or partly 
evanescent. Scutellum red. Abdomen with apical margins of the seg- 
ments, and the venter, pale stramineous; basal segment a little longer 
than hind coxae, basal fovea large and apically closed, discal carinae and 
sulcus traceable; terebra short and stout. Legs red and slender; hind 
tarsi and tibiae black, with the latter broadly white before their base. 
Wings with no areolet; stigma nigrescent, radix and tegulae whitish ; 
nervellus subopposite. Length,6 mm. Q only. 
This exclusively Swedish 9 is recorded from ‘‘Norwich,” with no 
intimation of its novelty as British, by Bridgman (Trans. Norf. Soc. 1894, 
p- 625). ‘There is a large 9 of 9 mm., undoubtedly referable to this 
species in Mus. Brit. ex coll. Desvignes, who thought it a form of JZ. 
opticus. Vollenhovyen’s figure with red mesonotum must represent a 
variety. 
33. opticus, Grav. 
Tryphon opticus, Gr. I. E. ii. 176; Ste. Ill. M. vii. 240, excl. ¢. Mesoleius 
opticus, Holmgr. Sv. Ak. Handl. 1855, p. 136, ¢; loc. cit. 1876, p. 33; Voll. Pinac. 
pl. xxiii, fig.4; Thoms. O. E. xix. 2074, ¢ ¢. 
Head not constricted posteriorly; mouth, the apically emarginate 
clypeus and in @ apices of the somewhat short cheeks and the face, 
whitish. Antennae with flagellum of ? subinfuscate, of ¢ ferrugineous, 
beneath. Thorax with lateral mesonotal vittae and dots before radices 
whitish ; at least the whole sternum red; mesopleurae shining and very 
finely alutaceous; metanotal areae complete with areola elongate and 
subrectangular. Scutellum red with its apex and postscutellum white. 
Abdomen with venter and apical margins of third to seventh segments 
white ; basal segment somewhat longer than hind coxae, its discal sulcus 
and carinae distinct, extending beyond spiracles ; second and third trans- 
verse, the former finely alutaceous. Legs normal and pale red; hind 
tarsi and tibiae black, with a white band before base of latter; ¢@ with 
front coxae and trochanters stramineous. Wings with no areolet; stigma 
infuscate, radix and tegulae whitish; nervellus subopposite. Length, 
8 mm. 
Holmgren placed this species between and considered it very closely 
allied to IZ, dubius and JM. furax, but Thomson in 1895 regards it as 
most closely related to A/. sanguinicollis, from which it differs in its emar- 
ginate clypeus, subopposite nervellus, very obsolete notauli, shorter 
petiolar area, longer petiolae with its narrower sulcus, as well as in the 
colouration of the thorax and hind legs. 
Austria, Nuremburg, rare in Sweden early in September; Brischke 
bred it in Prussia from larvae of Nematus fulvus (miliaris, Pz.) and of WV. 
pavidus (Schr. Phys. Ges. Kénig. 1871, p. 73) ; Vollenhoven says he raised 
this species, probably in Holland, from Mematus virescens, to which Gaulle 
adds from France Cimbex femorata and Pteronus Bergmanni, Dib. Stephens 
tells us he took it at Darenth wood in June, but his two extant females 
are reterable to J/. haematodes. Only once has it since been mentioned 
with us: ‘T. Wilson says (Yorkshire Naturalist, vi, 1881, p. 153) that he 
took it hovering at willow stumps containing larvae of Sesca bembeceformis 
at York; ‘‘these specimens came from the stumps, but whether from 
these larvae or not I am not prepared to say” (Trans. Yorks. Nat. Union, 
1882, p.107). I have seen nothing like it, 
