FAMILY SCOLYTIDAE 



599 



with a very fine row of small punctures down them ; declivity only moderately abrupt, striate- 

 punctate, with a moderately dense covering of spiny setae, which are also present on disk and 

 sides of elytra and on prothorax anteiiorly. Under-stirface light in colour, punctate, with 

 a few sparse spiny setae. Legs brown, tibiae with four teeth on outer edge anteriorly 

 and a terminal hook. Length, 2 mm. to 2.5 mm. 



This insect is one of the common pin-hole borers of teak in Madras. 



I took the insect riddling teak poles in Nilumbur in 



Life History. August 1902, and saw the results of its work on other 



occasions in these forests. The female appeared to 



drive tunnels into hard timber, laying her eggs at the bottom of the tunnel. 



Three years later I was able to make some further observations in 

 Tenasserim on this insect, which is new to science. 



A generation of beetles just mature and leaving a Dalbcrgia cultvata 

 tree was taken on Kowloon Island, Salween River, on the loth of March 

 1905. The insect evidently oviposits in nearly dead and newly dead trees. 

 To oviposit the beetle tunnels down through the bark till it reaches the 

 sapwood. On the outer surface of this latter a short transverse gallery 

 about an inch in length is eaten out (fig. 381, b, c), and the female 



beetle is probably fertilized by the 

 male here. From somewhere in this 

 gallery the female beetle tunnels down 

 into the wood, the tunnel curving at 

 first and then going straight down 

 into the wood for four to five inches (d). 

 In several cases two holes took off 

 from the transverse gallery, and 

 the male may pair with more than 

 one female. From the long tunnels 

 in the wood I took two, three, and as 

 many as four mature beetles which 

 were obviously just mature and re;ul\ 

 to leave the tree. The eggs are evi- 

 dently laid at the bottom of the tunnel 



FIG. 381. 



Egg-tunnel of Xyleborus noxiits. Samps., 

 in the wood rtDalber^ia cultrata. /r, bark ; 

 b, c, transverse gallery in outer sapwond : bv the female beetle, at least four eggs 

 d, egg-gallery. Salween River, Tenasserim. being laid in each tunnel. 



The infested tree examined was a large newly dead girdled standing 

 yindiak, a large part of the lower portion of whose trunk was literally 

 pitted with the entrance-holes of the insect. The attack in question was 

 evidently just over, and the wood too dry for further attack, as I found 

 none of the issuing generation of beetles tunnelling into tin- wood to oviposit. 



This is also one of the pyinkadu sr.olytid wood-borers. I took this 

 Xvlclionts numerously in March in a large live which had been felled 

 in a clearing at Kamamaung, Salween River, some four to six weeks 



