GRUBS OF BEETLES. 



399 



We liave frequently oliserved 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, no- 

 thing wonderful 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 galleries 

 between the bark and the wood ; and, in order not to 

 interfere with the 7^uns 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 each other's premises. We 

 cannot but admire the remarkable instinct implanted in 

 these grubs by their Creator ; which guides them thus in 

 lines diverging farther and farther as they increase in size, 

 so that they are prevented from interfering with the com- 

 forts of one another. 



Bark mined in rays by beetle-grubs. 



The various instances of voracity which we have thus 

 described sink into insignificance when compared with the 



