FAMILY SCOLYTIDAE 



499 



Crypturgus pusillus, Gyll. 



REFERENCE. Stebbing, Depart. Notes (Polygraphus minimus), i, 252. 



Habitat. North-West Himalaya. 



Tree Attacked. - The Blue Pine (Finns excelsa) ; Spruce (Picea morinda). 



Beetle. The beetle is very small, black, moderately shining, with elytra covered with 



scattered longish white hairs. Head small, vertical in front, with a very short rostrum. 



Antennae short ; scape thick, straight ; 

 Description. funiculus five-jointed ; club compact, flat- 



tened, ovate ; eyes oval. Prothorax cylin- 

 drical, narrower in front than behind, and uniformly pitted. Elytra 

 fairly long, rounded at the posterior declivity, not wider than pro- 

 thorax behind, pitted. Thighs of legs long-oval. Tibiae finely 

 toothed on their external edge ; tarsus filiform, the first three 

 joints of equal size, the third not bilobed. The three intermediate 

 segments of the abdomen of same size and short. Antennae and 

 legs yellowish brown. Length, i.i mm. 



\ 



Larva. The larva is a minute white curved grub. 



FIG. 325. 



Crypturgus pusillus, 

 Gyll. North - West 



Himalaya. 



This minute scolytid is very plentiful in the 



Western Himalaya, where it is 



Life History. to be found infesting both the blue pine and spruce. 



It only comes into the tree when the bark has 



commenced to dry, appearing at the time when a generation of the 

 Tomiciis ribbentropi is maturing and leaving the tree. The insect may 

 often be found in company with Polygraphus pini. So far as obser- 

 vations go it only infests the main stem of the tree, and only appears 

 in the inner bast. The male beetle tunnels through the bark of poles 



which have nearly reached their maximum height 

 development, or into that of old trees, and eats 

 out a pairing-chamber which is of considerable 

 size, though it is mostly hidden by a thin layer of 

 the inner bark. From this central chamber a number 

 of tiny curving galleries take off and ramify, each of 

 which is made by a female beetle. These egg-galleries 

 are quite short, about half an inch in length ; they 

 wind and curve about, and have a sharp hook-like 

 bend at the end in which the eggs are laid (see 

 fig. 326). Large areas of the inside bark are occupied 

 by these curious tiny curving and winding galleries, 

 where several pairing-chambers are situated near one 

 another. The male appears to fertilize at least six 

 ji female beetles, and the number may be greater. The 



patches have a rough resemblance to the plan of the 

 egg and larval galleries of a Scolytn-s (Eccopto<fii*tci-\ 

 beetle, but are infinitely smaller. 



On hatching out the grubs feed side by side, pro- 

 West Himalaya. (E. P. s.^ longing the mother egg-gallery for a short distance. 



I I 2 



FIG. 326. 



Egg-galleries of 



Crypturgus pusillus, 



Gyll., in spruce. North- 



