AFFECTION OP INSECTS FOn THEIR YOUNG. 347 



to reconnoitre. At first it climbed up the bank, but, as 

 if discovering- that this was not the direction, soon re- 

 turned, and, after another survey perceiving the hole, 

 took up the spider and dragged it in after it. 



In the two instances above given, one dead caterpil- 

 lar or spider only was deposited in each hole. But an 

 insect described by Reaumur under the name of the 

 mason-wasp (Epipone sjnnipes, Latr.), very common in 

 some parts of England, after having excavated a bur- 

 row, with an ingenuity to which on a future occasion I 

 shall draw your attention, places along v.ith its egg as 

 food for the future young, about twelve little green 

 grubs without feet, which it has carefully selected full 

 grown and conveyed without injuring them. You will 

 inquire. Why this difference of procedure ? With re- 

 gard to the choice of a number of small grubs rather 

 than of one large caterpillar, what I have said in a 

 former letter on the subject of different species of this 

 tribe being appointed to prey upon and thus keep within 

 due limits the larvae of different kinds of insects, will 

 be a sufficient answer. But one circumstance credi- 

 table to the talents of the mason-wasp as a skilful pur- 

 veyor should not be omitted, namely, that the number 

 of grubs laid up is not always the same, but is exactly 

 proportioned to their size, eleven or twelve being stored 

 when they are small, but only eight or nine when larger. 

 W^ith respect however to the caution of the wasp in se- 

 lecting full grown grubs and conveying them uninjured 

 to her hole, a satisfactory explanation may be given. If 

 those that are but partly grown were chosen^ they would 

 die in a short time for want of food, and putrefying 

 would destroy the inclosed egg, or the young one which 



