50 BRITISH ICHNF.UMONS [Peri I h oil s. 



the same time as the imagines of their hosts, are produced the hibernat- 

 ing larvae of the next winter. " For all Ichncumonidae," he continues, 

 "it is advantageous to have several hosts, in order that they may be able 

 properlv to place an egg wlien necessary. It is probable that our 

 Ephialtts only places its eggs in growing twigs, but in them it is desirable 

 to have as many chances as possible. The female Ephialtes can only 

 judge of present situation to a limited extent, and no one will believe she 

 can see into the future." He then refers to the case of eggs being laid 

 with Hoploptis l(7i'7'ipi's, which is single brooded, with the result that the 

 resulting imagines perish, since they can break through neither the hard 

 shell of the host nor the surrounding bark of the Ruhiis twig; conse- 

 quently the instinct to oviposit in single brooded hosts is not propagated 

 to the offspring of so mistaken a parent. Next follows a table showing 

 that in the cases of Chevrinia and Psen the parasite emerges at the same 

 time as, or at most a couple days before, its host. This he considers of 

 importance, since, if it appears a little before its host, it either waits for 

 the latter's emergence or, in spite of its weak jaws, works its wa}' out 

 unassisted, and in either case j^ropagation is assured ; but if, on the other 

 hand, it does not emerge till after its host, those in the back cells of the 

 Riibus twig will work through and injure or e\'en kill the delicate nymph 

 of the parasite in passing over it to the outer world. He makes no refer- 

 ence to the usual Ichneumonid habit of remaining quiescent for a period 

 after having discarded the pupal envelope. 1 have discovered no des- 

 criptions of the larva or nvmph of this well-known and oft-bred insect. 



THERONIA, Holmgren. 



Holmgr. Ofv. 1859, p. 123: Sv. Ak. Handl. 1860, n. 10, p. 16. 



Head short, transverse and declived behind the ocelli; clypeus not 

 elongate, slightlv elevated transversely in the centre and apically truncate; 

 mandibles somewhat broad, with the apical teeth of equal length ; eyes 

 oblong, touching base of mandibles and emarginate next the scrobes. 

 Antennae somewhat short and stout, filiform, with the scape externally 

 excised and flagellar joints cylindrical. Thorax impunctate, stout and 

 gibbulous, a little longer than high; notauli apically distinct; metanotum 

 areated, spiracles large and elongate.' Scutellum convex. Abdomen 

 very smooth and not punctate discally; segments transverse and some- 

 what uneven, with the basal canaliculate ; terebra emitted from a ventral 

 fold, a third or a half the length of the abdomen. I-egs somewhat stout, 

 with the hind ones subincrassate ; claws simple, pulvilli large ; hind femora 

 crenulate apically beneath. Wings witli areolet sessile and irregularly 

 subpentagonal. 



This genus differs from Pinipla [s.s.), wliicli it strongly resembles in 

 shape and general fecies, in its iminmctate and entirely glabrous abdomen 

 and incrassate hind femora; it may also be instantly recognised by the 

 conspicucjus coloration of its single species. 



1. atalantae, Poda. 



Iclineiniioti Atalantae, Poda, Ins. Graec. 106. /. speculator, Scop. En. Car. 

 753. /. scutellatiis, Fourc. E. P. 402. I.flavicans, Fab. E. S. ii. 182. Piiiipla 

 flavicans, Fab. Piei!.119; Gr. L E. iii. 141; Ratz. Ichn. d. Forst. i. 118; ii. 97, 

 <? ? . Tlieronia flavicans, Holmgr. Sv. Ak. Handl. 1860, n. 10, p. 16, ^ ; Tasch. 

 Zeits. Ges. Nat. 1863, p. 52 ; lib. cit. p. 250. <? ?; cf. Veil. Schets. I, pi. iii, 

 fig. 19. 



