NATURAL HISTORY SOCIETY OF GLASGOW. 205 



both agree perfectly with the larva of luconim, so common every- 

 where in our birch woods ; but these authors make no mention of 

 the imago varying in the manner I have indicated. 



Van Vollenhoven has described a birch-feeding larva as that of 

 lateralis, Leach, and this larva seems to be the same as that of 

 lucorum ; or if it is not, then there must be two species attached 

 to birch, with similar larvae, namely, lateralis and lucorum. But 

 lateralis has always been regarded as synonymous with vitellinaey 

 and that is, so far as we know, confined to willows. It was 

 well described by De Geer (Mem. ii., 232, pi. xxxiii., f. 17-22), 

 and there are excellent figures of the larva in Brischke and 

 Zaddach's work, their observations and descriptions being quite 

 in accordance with mine ; that is to say, that vitellinae is purely a 

 willow-feeder. Van Vollenhoven, again, has described the true 

 lucorum as a birch-feeder. We must, then, either suppose that 

 the Dutch Hymenopterologist has described the same larva under 

 two different names (in his plate he does not give an original 

 figure of lateralis, but copies that of Curtis), or that vitellinae feeds 

 both on birch and willow, and that the birch-feeder, as a larva, 

 difters considerably from that attached to Salix. The latter seems 

 to be Van Vollenhoven's own opinion, for he quotes De Geer's 

 descriptions as referring to vitellinae. The matter, however, 

 requires confirmation; at any rate, I am certain that, in the 

 perfect state, lucorum has frequently (more especially in bred 

 specimens) the abdomen more or less coloured as in vitellinae, and 

 our descriptions of it must be modified accordingly. The subject 

 being thus a little confused, I give descriptions of the larvae of 

 our four species of Trichiosoma : — 



Sorbi, Htg. — Head small, ochreous-yellow, with two dark 

 reddish marks on the vertex, which are frequently almost, if not 

 quite, joined together; mouth brownish, mandibles blackish. 

 Body yellowish-green; the skin beset with numerous tubercles, 

 which are white with a yellowish tinge, and are much larger over 

 the legs and along the dorsal vessel than over the rest of the 

 body ; there are none on the anal segment. Legs white, with 

 dark brown claws, abdominal legs glassy green. Spiracles eliptical, 

 pinkish-red. The clypeus and the part immediately above it is 

 whitish, without the ochreous colour. 



"When young it is whitish green, with white tubercles ; the skin 

 deeply powdered. The head is pale ochreous-yellow. 



