482 



FAMILY SCOLYTIDAE 



the main stem or thicker branches at an angle, and hollows out to one side 

 of the tunnel a small chamber, large enough to afford space for two beetles 

 i tig. c). This is the pairing-chamber. The female usually enters the 

 pairing-chamber by boring a separate tunnel through the bark, which 

 hits off the chamber. She is fertilized by the male, and then continues the 

 entrance-tunnel down to the bast. On reaching this she eats out a 

 gallery in the longitudinal axis of the tree approximately at right angles to 

 the entrance-tunnel. This is the egg-gallery, and is about an inch in length. 

 The eggs are laid in this, and the larvae hatch out and mature in a manner 

 similar to that already described for S. siwalikensis (p. 477). The larval 

 tunnels are winding; they increase in size with the growth of the grub, and 



FlG. 318, -Sphaerotrypes dssaniensis, Steb., in the sal-tree in Assam, a, male ; 

 b, female beetle ; c, entrance-galleries of male and female beetles and pairing-chamber 

 in the bark ; d, egg and larval galleries; e,f, uncompleted egg and larval galleries 

 in green trees full of sap. Assam and Bengal Duars. 



are tightly packed with the wood excreta. The plan of egg and larval 



very constant and uniform, forming a bluntly rounded ellipse 



Vhen numerous the beetle will lay its eggs in small branches. On 



the bark is necessarily too thin for the beetle to hollow out its pairing- 



iber in it, and instead this latter is made in the sapwood and bast. 



Cillery is commenced to one side of the pairing-chamber, the latter 



situated about an eighth of an inch up the former and to one 



^he egg-gallery is not invariably straight. It may be curved or 



