334 



FAMILY CERAMBYCIDAE 



should be fully worked out. Where the eggs are laid, the number laid in 

 one beetle-tunnel or on the larva, how the grub feeds upon the beetle-larva, 

 whether the latter is usually killed before making its calcareous covering to 

 the pupal chamber, how the fly leaves the tree, and the number of generations 

 of the insect in the year, are some of the points requiring investigation. 



Bothrideres? sp. (p. 112) The grub of this beetle apparently feeds upon 

 the Hoplocerambyx grub as an external or internal parasite, eventually killing 

 the latter before it pupates. 



Cocoon. The cocoon consists of a yellowish-coloured parchment material which appears 

 to be made of very closely spun fine fibres of a ligneous nature. It is elliptical in shape 

 and 4.2 mm. in length. The cover was spun with a few 

 fine silk threads to the shrivelled skin of the cerambyx 

 larva. 



Beetle. Elongate, narrow, reddish brown in colour. 

 Thorax square, anterior margin concave, disk convex, 

 punctate. Elytra moderately convex, punctate-striate. 

 Length, 5.8 mm. Fig. 221 shows cocoon, beetle, and a 

 shrivelled skin of a Hoplocerambyx larva. 



FIG. 221. 



Life History. In a larval gallery of H. 

 spinicornis, opened out whilst splitting up a 

 green sal-tree felled in the Kachugaon forests 

 on 16 May 1906, a blackish shrivelled skin of 

 the grub of this beetle was found. The larva 

 had been engaged in eating out the gallery in 

 the heart-wood which finally terminates in the 



pupal chamber, and had died from exhaus- Bothrideres ? sp. Cocoon and 



, . . beetle. Shrivelled skin of Hoplo- 



tion whilst performing this operation. Beside ce rambyx\avr* (on the left) from 

 the shrivelled skin was the small elliptical which the beetle was bred. Assam. 

 cocoon described above. Both skin and 



cocoon were transferred to a tube and kept under observation. An 

 examination of the tube on 19 May disclosed the fact that one-half 

 of the cocoon had been eaten down longitudinally, a reddish-coloured 

 beetle being observable inside. No material change occurred on the 2Oth. 

 On the 2ist an inspection showed that the beetle had eaten almost all the 

 cocoon away and had emerged from it. 



I explain the life history as follows : The colydiid larva feeds upon 

 the longicorn grub either externally or internally, most probably the former, 

 parasitically, the grub eventually dying of exhaustion. The parasite then 

 spins a cocoon, which it attaches to the drying skin of the dead grub, and 

 pupates. 



Whilst this insect is a most useful one, further observations are 

 required to ascertain its abundance in the forest before its value as an 

 aid towards keeping down the sal-borer pest can be decided. The points 

 in the life history already given under the Ichneumon parasite require 

 investigation in the case of this insect also. 



