126 



BRITISH ICHNEUMONS. 



\Polysphincta. 



y^i-x. 



Bignell has also bred this species in south Devonshire on 13th August 

 from a spider Mcta illcrianar, Scop., upon which he says it is ektoparasitic. 

 Beaumont took a (J at Oxshott in July, 1893. 



In mv garden at Monks' Soham I beat a young Epcira cucurbHina, 

 Clerck., from an apple tree on June ist, 1907, with one of these larvae 

 wrapped like a muffler round its neck (fig. i). The 

 larva's tail is just above the left hind coxa ; its head 

 in the centre of the side of the abdomen ; the head 

 (fig. 2) is dark and chitinous, and not at all inserted 

 in the spider's body ; the lateral lobes usual in 

 ichneumonidous larvae which Laboulbene failed to 

 notice accurately, are wanting, at all events at this 

 stage of its life ; it was then darkish grey with the 

 head brown and I only detected thirteen segments 

 in all. During the 2nd, 3rd, and 4th of June the 

 larva continued to suck the spider without mo\ing, 

 growing very gradually in bulk, to the no apparent 

 inconvenience of its host ; but on the morning of the 

 5th it had evidently shed its skin (though no vestige 

 of it was discoverable) since it now possessed, in 

 place of the ordinary segmentation before shown, 

 eight very distinct dorsal prolegs, a much attenuated 

 Cauda and a pale grey head with a central longitudinal 

 line and two oblique ones on either side of it paler. 

 It had, too, moved its head from the lateral position 

 shown in fig. i, to the very centre of the host's 

 abdomen, immediately behind the hind coxae. By the evening of the 5th 

 the abdomen was sucked quite dry and the larva had, without relinquish- 

 ing the position of its tail — which appeared immovable throughout its 

 actively vampire state — taken up a longitudinal position and was sucking 

 each leg individually. By the morning of the sixth, the spider, excepting 

 a leg or two which still afforded nutriment, was quite consumed, and the 

 larva was attached entirely to the web by its dorsal prolegs, each of which 

 terminates in about a hundred (I counted them) black hooks, arranged in 

 three subirregular concentric circles. It is now olive-green, with two 

 dark streaks on the frons and the inner side of the eyes blackish ; there 

 is I think no doubt that these are true eyes, except for which the capital 

 markings are sufficiently similar to those of entomophagous ichneumoni- 

 dous larvae {cf. jMcsostenus obnoxiiis, I.B. ii, 261, &c) ; the head is as 

 shown in fig. 2, with the body throughout setiferous as shown in the 

 second segment behind the small head. When annoyed, the larva moves 

 vertically — not horizontally, cf. supra — with strong jerks, but does not 

 move its tail. It is still curled longitudinally round the empty spider's 

 skin, and is much attenuated anally. At 5 p.m. on the oth, the parasite 

 had discarded its host and begun to spin a web. At 10 p.m. on the 8th, 

 the cocoon was shaped and at 10 p.m. on the 9th, it had become notably 

 thicker and was pure white. On the i oth the cocoon was completed and at 

 10 a.m. on the i ith black exuviae had been ejected through the anal end of 

 the cocoon. A female P. multicolora had just emerged on the 3rd July and 

 was dead, though still quite soft. On the 5th of August, 1905, 1 took a 

 male of the same species on the window of my house here. 



