GRUBS OF BEETLES. 245 



apparent discrimination whether these are the 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 ( Scolytus 

 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 un- 

 der cover. They dig, therefore, long tubular galleries 

 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 al- 

 ways in a right line, yet, however near they may ap- 

 proach to the contiguous ones, none of them ever 



Bark mined in rays by beetle grubs. 

 * J. R. See also De Geer, i, 533, &c, apd R aumur, ii, 413, 



VOL, vi. 21* 



