252 OBSERVATIONS ON INSECTS. 



appearance of a nest to be found near them. I be- 

 lieve these caterpillars to be brought by some species 

 of Odynerus, as the circumstance generally occurs 

 at the time that these insects are in the habit of 

 entering houses ; but why they should be left there, 

 and deserted, in such numbers, and not availed of 

 for the purpose for which they were originally car- 

 ried off, I am at a loss to conjecture. Is it because 

 they are discovered afterwards to be too small, and 

 not full-fed,* or from any circumstance unconnect- 

 ed with the particular state of the caterpillar ? Be 

 the cause what it may, there the caterpillars remain 

 till they waste and die. 



I conceive it to have been some species of mason- 

 wasp, which was once the cause of much inconve- 

 nience to me, from the circumstance of its construct- 

 ing its nest in the lock of a drawer. It was on the 

 26th of September 1837, that, on my return home, 

 after an absence of six weeks, I attempted in vain to 



* Kirby and Spence seem to speak as if the mason-wasps 

 generally selected full-grown grubs as food for their future young. 

 They observe, that " if those that are but partly grown were cho- 

 sen, they would die in a short time for want of food, and putrefy- 

 ing would destroy the inclosed egg, or the young one which 

 springs from it. But when larvae of any kind have attained their 

 full size, and are about to pass into the pupa state, they can exist 

 for a long period without any further supply. By selecting these, 

 therefore, and placing them uninjured in the hole, however long 

 the interval before the egg hatches, the disclosed larva is sure of a 

 sufficiency of fresh and wholesome nutriment." Vol. i. 1st edit. 

 p. 341. 



