72 Indian Museum Notes. [Vol. V. 



4. Xyleborus, sp. 



References.— Gage, Department Land Records and Agriculture, Bengal, Bui. 



No. 7, 1900. 



Classification. — Order Coleoptera. Family Scolytidce. 



This beetle has not at present been fully identified, but it is con- 

 sidered probable that it will be found to be closely allied to Xyleborus 

 perforans, the beetle popularly known as the "shot borer" which 

 does so much damage to the sugarcane in the West Indies. 



I propose here giving a description of the genus Xyleborus, and 

 a few notes on the life history of the West Indian X. perforans, as it 

 is more than probable that our Indian form will be found to have 

 identical (or nearly so) habits. 



THE GENUS Xyleborus. 



It is distinguished by the following characters : Beetles, small and 

 cylindrical. Head globular, hidden under a rounded or cylindrical 

 thorax, whose anterior half is densely asperate, or grater-like, the 

 hinder half smooth, and finely punctured. Prothorax excised vent- 

 rally up to the anterior coxae. Tibiae flattened, dilated towards the 

 apex, with the outer edge rounded and serrate; the tarsi can be 

 folded up against them. 



Body cylindrical, elytra punctured in rows, without a depressed 

 line along side of suture. Males much smaller than females, of 

 shorter and more convex shape, they are wingless, and fertilise the 

 females in the plant when they are bred. They are by far the 

 rarer of the sexes, the relative numbers varying from about one 

 in four up to one in 30 or more, according to the species. 



Life History : EGG. — In the case of X. perjorans the females are 

 fertilised by the wingless males in the burrows when they are born 

 and never in the air. The female enters by a hole made in a node 

 and bores out a series of galleries near the node in which the eggs 

 are laid. 



LARVA. — The larva is a minute white footless grub. Head 

 horny and white, the jaws being tinged with brown. They are 

 supposed to feed on the juices of the cane, the burrowing being 

 almost, if not entirely, done by the female. 



The larvae are soon hatched and feed for about l\ months. 



Pupa. — The pupae are found in the galleries, they are white, 

 about the length of the perfect insect, and of the ordinary beetle 

 type. The insect spends from two to three weeks in this stage. 



