348 FAMILY CERAMBYCIDAE 



Owing to an unfortunate mistake made in the identification of speci- 

 mens of this insect some twelve years ago, it became 

 Life History. confused with the Xylotvechus of the Himalayan oak, 



Qneycus dilatata, leading to the supposition that 

 there were two species of Xylotrechus infesting this oak. So far as 

 my present observations and information go only one, X. Stebbingi, is 

 known. 



X. smci, quoted variously as Clytus vicinns and Xylotrcclins vicinus, 

 pseudonyms which gave rise to the mistake, infests the sal-tree in the 

 Siwaliks. Notes on the life history of this insect were made by me 

 some years ago, the insect being identified as Clytus vicinus. The 

 beetles appear on the wing in June, and not improbably again at 

 the end of September or in October, there thus being two genera- 

 tions of the insect in the year. The eggs are laid in sickly trees or 

 newly felled ones, but always in the upper part in the crown or larger 

 branches, or in the main stem of younger trees. The larvae live in the 

 bast and sapwood, eating deeply into this latter when infesting the 

 smaller branches. When full-fed they go further into the wood and 

 eat out a small elongate pupal chamber (cf. fig. 237 (3)) which is 

 more or less parallel to the longitudinal axis of the branch or stem. Here 

 they pupate. The beetle, on maturing, crawls up the tunnel, eats a hole 

 in the bark, and escapes. 



Larvae of varying size but mostly quite small, taken numerously in 

 tops and large branches in January, pupated in May and issued in June of 

 the same year. I am of opinion that these June beetles lay eggs which 

 hatch, and the resultant larvae become full-fed in September, a fresh 

 generation of beetles issuing in October. I also took this insect in all its 

 stages of larva, pupa, and beetle from a recently felled large teak-tree at 

 Wutgyi on the Salween River in Tenasserim on 7 March 1905. The tree, 

 according to the villagers, had been felled from a month to six weeks before. 

 As some of the larvae had not only reached full size, but pupated, and the 

 beetles were nearly ready to issue (one actually was mature), the period must 

 have been longer, provided that the eggs had not been laid in the tree before 

 it had been felled. It is perhaps most probable that the eggs were laid on 

 the tree in November or December, which would indicate that there are 

 two life-cycles in the year, since one generation of the beetles issues some 

 time in March. 



In Tenasserim the grubs were found feeding in the bast and sapwood, 

 eating out irregular shallow tunnels which are always tightly packed with 

 excreta ; when full-fed the grub bores down half an inch or so into the 

 sapwood, and then carries the tunnel parallel to the long axis of the tree, 

 slightly enlarging it to form the pupal chamber. In its method of 

 pupating it greatly resembles the Xylotrcchus found infesting the Tcnninalia 

 tomcntosa in the same locality (p. 353^. 



