RAVAGES OF BEETLES. 245 



parent discrimination whether these are tlie progeny 

 of their own mother, or of a different species.* 



We have frequently observed a very remarkable 

 instinct in the grubs of a species of beetle {Scolitor 

 Destructor, Geoffroy), which lives under the dead 

 bark of trees. The mother insect, as is usual with 

 beetles, deposits her eggs in a patch or cluster in a 

 chink or hole in the bark ; and when the brood is 

 hatched, they begin feeding on the bark which had 

 formed their cradle. There is, of course, nothing won- 

 derful in their eating the food selected by their mother ; 

 but it appears that, like the caterpillars of the clothes- 

 moth, and the tent insects, they cannot feed except 

 under cover. They dig, therefore, long tubular gal- 

 leries between the bark and the wood ; and in order 

 not to interfere with the runs of their brethren, they 

 branch off from the place of hatching like rays from 

 the centre of a circle : though these are not always 

 in a right line, yet, however near they may approach 

 to the contiguous ones, none of them ever break into 



Bark mined in rays by beetle-grubs. 

 * J. R. See also De Geer, i. 533, &c., and Reaumur, ii. 413, 



r3 



