The Mason-Wasps 



positive condition being that the temper- 

 ature should be mild and equable. A 

 furnace heat appears to suit the Pelopaeus' 

 larvae; at least, the favourite place is the 

 chimney, on either side of the flue, up to a 

 height of twenty inches or so. This snug 

 shelter has its drawbacks. The smoke gets 

 to the nests, especially during the winter, 

 when fires are going all day, and gives them 

 a glaze of brown or black similar to that 

 which covers the stonework. They are so 

 like it in appearance that they might well be 

 taken for inequalities in the mortar which 

 have been overlooked by the trowel. This 

 swarthy distempering is not a serious mat- 

 ter, provided that the flames do not lick 

 against the cluster of cells. That would 

 ensure the destruction of the larvae, stewed 

 to death in their clay pots. But this danger 

 appears to be foreseen; and the Pelopaeus 

 entrusts her family only to chimneys which 

 are too wide for anything but smoke to 

 reach their sides; she is suspicious of the 

 narrow ones which allow the flames to fill 

 the whole entrance to the flue. 



In spite of her caution, one peril remains. 

 While the nest is building, at a moment 

 when the Wasp, urged by the need for lay- 

 ing her eggs, cannot bring herself to cease 

 62 



