Mesos/enus.] BRITISH ICHNEUMONS. 263 



Bignell is of opinion that this species confines its parasitism (in Britain) 

 exclusively to Zygaena filipendtilae, and arrives at this conclusion, which 

 is not entirely correct (see Hanim's record, etc., above), by observing, 

 through many years, that it does not emerge from its host's cocoon until 

 the caterpillars are full grown and consequently in a fit state for ovi- 

 position ; at all events all the formerly recorded emergences, and these 

 are comparatively numerous, have been from this host, which always 

 succeeds in weaving a perfectly formed cocoon. I have attempted to 

 induce bred se.xes to co[)ulate in the presence of Zygaena larvae ; when 

 first introduced the $ attempted advances which were repulsed by the $ , 

 who made a feint of piercing the larvae with her spicula, but the action 

 appeared instinctive rather than deliberate, and the experiment failed. 



M. obnoxius appears to be a local species ; more than half the speci- 

 mens I have examined are from Reigate. At Felixstowe I have collected 

 over a hundred cocoons of Z. filipendulae, not one of which exhibited a 

 trace of this species. Bignell (Entom. 1880, p. 17) bred twenty specimens 

 from seventy cocoons of the host, which also produced a couple of Tachina 

 lan'arum, three Exorista vulgaris and five Apanteles sp. (probably A. con- 

 gestus, as bred from this host by Brischke ; see also Ent. Rec. 1902, p. 349^); 

 and even these are not all the ills that this poor moth is heir to, since 

 Anomalon fibulator is said to be frequently parasitic upon it, and Spilo- 

 cryptus fumipennis is another enemy. I have, moreover, dealt somewhat 

 fully with the hyperparasitism of Hemiteks castaneus, through M. obnoxius, 

 under the former species. 



3. albinotatus, Grav. 



Mesostenus albinotatits, Gr. I. E. ii. 756; Tasch. Zeits. Ges. Nat. 1S65, p. iio, excl. 

 var. I, c5 9 ; (f. Brisch. Schr. Nat. Ges. Danz. 1879, p. 337 f/ Thorns. O. E. xix. 21 17. 

 Stenaraens albinotatus. Thorns, lib. cit. xxi. 23S2. 



Head narrowed behind the eyes ; frons coarsely punctate and mutic ; 

 oral costa not elevated ; internal orbits, especially in $ , whitish. An- 

 tennae of $ with three central joints white above. Thorax sub-cylindrical, 

 sometimes with a white dot beneath the radix ; epomiae short, apophyses 

 sub-obsolete. Scutellum with basal carinae more or less white. Abdomen 

 elongate, sub-fusiform ; black with post-petiole, whole of second segment, 

 and usually of the third, red ; margins of the sixth and seventh milky 

 white ; petiole acutely dentate laterally at the base ; post-petiole longer 

 than broad, smooth, with short spiracular but no dorsal carinae ; second 

 segment nearly twice longer than broad ; terebra nearly as long as the 

 abdomen, slightly deflexed. Legs not stout, red, with coxae and tro- 

 chanters black ; hind tibiae and tarsi, and sometimes in 9 femora basally 

 with the hind ones beneath, infuscate ; hind tarsi of c^ centrally white. 

 Wings somewhat clouded ; radix and tegulae infuscate ; discoidal cell 

 twice broader at apex than at base ; areolet transverse, nearly twice broader 

 than long. Length, 9-1 1 mm. 



1 With regard to Apanteles coiiRestus, I may say that in July, 1899, Mr. Prideaiix sent me a 

 cocoon of Z. plibendulae from which a perfect moth had already emerged and, attached to it, was 

 that of tliis species whose single larva had subsisted upon the caterpillar with no apparent iletriment 

 to it. Is it possible for a parent fly, disturbed in oviposition, to leave so slender a progeny for its 

 host to rear that the latter may sometimes survive to perfect maturity ? One would suppose the con- 

 tinual drain upon its strength of even a single Apanteles larva to be fatal (cf. also K.M.M. i. p. 73 et 

 Entom. 1866, p. 28). I do not eo so far as to assert that six specimens of I'aniscus crphatotes and a 

 perfect Arctia menthrasti could emerge from a single pupa o( Dicranura vinula ! (c/. Dale, Mag. Nat. 

 Hist. No. 19). 



