FAMILY PLATYPODIDAE 



seem to indicate that the material upon which the larvae feed is purely a 

 growth of sap origin, and that the reason for the beetle remaining alive is to 

 be sought rather in the protection she affords to the eggs and larvae when 

 hatched out by blocking her tunnel against the entrance of predaceous 

 insects and their grubs (in a manner similar to that of Scolytus major and 

 S. minor], than in any attempt on her part to provide food for her offspring. 



The female gallery is never carried into the hard rings of the heart- 

 wood, though it reaches down to them, and may have penetrated the tree to 

 a depth of from 6 in. to 12 in. or more when the sapwood is very thick. 

 The insect burrows into the tree in an indiscriminate manner, the thickest 

 end of the butt of trees, 6ft. in diameter, being attacked equally with the 

 top end of the stem and the thickest of the branches. It will only infest, 

 however, deodar-trees with absolutely fresh sapwood, and so far as present 

 observations go it appears only to bore in through the fresh bark and 

 will not attack barked logs. 



The beetles to be found at the end of June are laying the eggs of the 

 second generation of the year. 



A third generation of beetles have been taken in October laying eggs. 



This Crossotarsus is more active than the ordinary platypids, and it 

 walks at a comparatively good pace when outside its tunnel. It is active in 

 daylight, and tunnels into a log on the ground as much on the side on which 

 the sun impinges as into the parts in shade. 



I first took this insect in Jaunsar and Tehri Garhwal in 1902, and have 

 since found it numerously in newly felled green deodar logs in Chamba. It 

 is probably distributed throughout the deodar tracts of the North-West 

 Himalaya. 



In June 1902 I cut some dead specimens of this platypid from the wood 

 of a large girdled dead spruce in Tehri Garhwal. I could find no living 

 beetles that year. Towards the end of June 1909 I discovered the beetle on 

 the wing at Kainthli in Chamba. The beetles were tunnelling through the 

 thick bark of a dead spruce, felled four months previously, to oviposit. This 

 tree was in a drier state than I have ever found the insect in in deodar. 

 The spruce beetles were observed 

 to be pairing, the female entering 

 by the same hole as the male, or 

 vice versa, the insects pairing in 

 the outer sapwood. The female 

 then carries the tunnel in the sap- 

 wood in a series of zigzag curves 

 parallel to the circumference of 

 the tree, and about two inches 

 in. The tunnel then turns, and 

 goes zigzagging down into the 

 wood. There are no offshoots 

 to the tunnel, the latter ending 



|.- 1(; . 390 . 



K-g-tunnel of 

 in spruce. Chamba, X.\Y. Himalaya. 



, Stel>., 

 (E. P. S.) 



