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CHAPTER IX. 

 POLYMORPHA (continued) Family BOSTRYCHIDAE. 



THE Bostrychidae are a family of small elongate cylindrical beetles of 

 circular section who in their ovipositing operations make pin-holes and 

 " shot " holes in wood and bamboos. Owing to this habit of the beetles 

 their work is probably better known to the public throughout India than 

 is that of most of the other Indian forest insects. Whether the beetles 

 themselves actually derive sustenance from the wood has not yet been 

 proved. Their habit of tunnelling into it is at any rate primarily to oviposit 

 in the interior, the larvae being entirely wood-eaters. Most of the Indian 

 bamboos and the wood of a variety of trees are made use of for this 

 purpose. 



Some of the beetles are well known owing to their making their appear- 

 ance in numbers in the bungalow at the periods at which they mature and 

 swarm, either from neighbouring forest trees, or from the roofs, walls, and 

 floors of the bungalow itself. They also issue from the furniture, especially 

 bamboo-made articles. Many of the species appear to fly equally readily 

 by day or night. 



In spite of their small size, the largest being about one-third of an inch 

 in length, they are easily recognizable, owing to their cylindrical form and- 

 dark brown or black colour, and to the hooded prothorax, which is often, 

 serrated and rasp-like on the anterior surface. 



The beetles greatly resemble and are often mistaken for Scoly- 



tidae, the bark beetles. From these they may be 



Beetle. distinguished by the afore-mentioned tuberculate 



and rasp-like prothorax, by the straight inste;i 1 of 



elbowed antenna, which has a three-jointed club at its end, and ly the 



five-jointed tarsi, the first or basal joint 



of which is small, the second and fifth being 



long. The outer integument or covering of 



the beetle is very hard, all the parts fitting 



well together, as is usually the case with 



wood-boring insects. The prothorax is 



occasionally furnished with hooks or front, 1 1 



teeth in addition to the enlarged tuberm- 



lations, whilst the body is provided with one 



or more tubercles, probably used by the 



beetle in moving in its tunnel in the wood. 



The legs have broad femora and tibiae, the latter sometimes toothed 



one edge. 



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