THE SOCIAL INSECTS 



the male and female also co-operate in rolling pellets of dung 

 to the mouth of the burrow, and both parents may stay in the 

 burrow until the young beetles of the next generation are 

 ready to leave it. In the burying beetles a male and female 

 co-operate in burying small dead animals by digging away 

 the earth from underneath them. The pair of beetles then 



Fig. 7 

 Left, an ambrosia beetle, Platypus cylindrus. Right, a bark beetle, 

 Xyloborus saxeseni. (Redrawn from Munro) 



live in a chamber surrounding the mass of carrion. The female 

 lays her eggs in the earth, in the walls of a tunnel leading out 

 of the chamber. After about five days, the young larvae hatch 

 and burrow through the soil to reach the chamber. Here, up 

 to the first moult, and for a short period after each succeed- 

 ing moult, they are fed by the female on regurgitated food. 

 It has been found that though some of them may develop 

 without this attention a much smaller proportion do so 

 successfully. 



36 



