ix] ACULEATE HYMENOPTERA 125 



about in the now nearly cool oven. The moderate 

 temperature merely hastens the emergence of such 

 wasps as are nearly ready to come out from their 

 cocoons. When the nest has been thoroughly baked 

 some formalin should be squirted into it, or some 

 powdered naphthaline shaken well into it before it 

 is put aside in its permanent quarters. Much in- 

 formation regarding the development and life-his- 

 tories of many species may be obtained by rearing 

 the larvae in captivity. It is not difficult during 

 the summer to mark down spots where Fossors or 

 solitary bees are engaged in excavating their bur- 

 rows : from such places the larvae or pupae may be 

 dug up with a spade from the depth of about a foot 

 in the autumn, and be taken home for closer obser- 

 vation. Both larvae and pupae have very soft and 

 tender skins and are easily injured: it is thus best 

 to avoid handling them, and to move them only with 

 a soft paint-brush. They should be kept in a box 

 whose bottom is covered with some soft material, 

 so that an accidental fall shall not result in injury. 

 The larvae of many species can be obtained from 

 rotting tree stumps, branches, posts and so forth, 

 and from the stems of brambles. Primings from 

 wayside hedges will often yield considerable num- 

 bers. The chief difficulty in all cases is to preserve 

 the proper degree of moisture in the boxes in which 

 the larvae, etc. are kept through the winter. If they 



