FAMILY SCOLYTIDAE 475 



Beetle. Elongate cylindrical ; black, shining, uniformly punctate. Smaller than hima- 

 layensls. Head with vertex smooth, with a few scattered fine punctures ; the transverse 



depression below vertex more prominent 

 Description than in hhnalavcnsis ; rostrum wide, 



scarcely constricted, and not carinate ; front 



uniformly pitted \\ith small punctures more prominent than on 

 vertex. Prothorax shaped as in himalayensis ; the punctation is, 

 however, quite different, the punctures being uniform in size and 

 arranged in symmetrical, longitudinal, parallel, equidistant rows 

 save near apex, where they are closer together ; on anterior margin 

 a. smooth area finely punctate, broadest medianly, thinning out 

 laterally on either side. Elytra with a slightly reddish tinge, a 

 little wider than thorax and nearly three-fourths as long again, FlG. 313. 



as wide at apex as at base, somewhat constricted in basal third, Hylastes lonqifolia, 

 apex bluntly rounded. Striate-punctate, striae deep, punctures small Steb. N.W. Himalaya, 

 and very uniform, interstices prominent, smooth, shining. Both 



upper and under surfaces are distinguished by an absence of hairs. Lender-surface black, 

 uniformly punctate ; punctures large save on abdominal segments, which are finely pitted. 

 Middle coxae closer together than in himalayensis. Length, 2.6 mm. to 3.05 mm. 



This beetle comes into the tree as the Tomicus and Polygraphus bark 



beetles of this pine, described later on, are leaving it, 



Life History. i.e. it does not require the bark and wood to be as fresh 



as is the case with the others. This I have noticed 



to be the rule with the Hylastes of the blue pine and spruce. The insect 



will not, however, attack dry wood. 



The beetle bores through the bark down to the inner bark layer, 

 and makes a central pairing-chamber from which radiate several (two or 

 more) galleries (filled with white wood-powder) in a fan-shaped manner. 

 These galleries, after zigzagging in the bark for some distance, are then 

 carried down into the wood at an angle which may be very acute or 

 otherwise. The zigzag gallery in the bark varies greatly in length ; it may 

 be very long or very short. This gallery grooves both bark and wood 

 and is rilled with white wood-dust, and so is easily seen in the dark- 

 red inner bark. After entering the sapwood the beetle may turn and bore 

 in it in a direction parallel to the circumference of the tree for a time, 

 and then again turn and bore right down into the heart-wood of the tree. 

 This procedure agrees with that of the Hylastes of the blue pine and spruce. 

 The deep tunnel in the wood is to lay her eggs in. The probable procedure 

 is that the male bores down to the inner bark, the females pair with him 

 there and then eat out their zigzag galleries in the bark, subsequently going 

 down into the wood. 



A generation of this beetle was found tunnelling into trees to ovi- 

 posit in late May and early June in Kumaun and in the middle of 

 June in Charnba, whilst another generation was taken, occupied in a 

 similar manner, towards the end of October in the Tons Valley, in Tehri 

 Garhwal. 



