The Mason-Wasps 



impassive, do not interfere, a clear proof 

 that the grub visited is in no peril. The 

 stranger, in fact, retires with a soft, glid- 

 ing motion. The chubby babe, a sort of 

 india-rubber bag, resumes its original volume 

 without having suffered any harm, as its ap- 

 petite soon shows. A nurse offers it a 

 mouthful, which it accepts with every sign of 

 unimpaired vigour. As for the Volucella- 

 grub, it licks its lips for a few moments after 

 its own fashion, pushing its two fangs in and 

 out; then, without further loss of time, it 

 goes and repeats its probing elsewhere. 



What it wants down there, at the bottom 

 of the cells, behind the grubs, cannot be de- 

 cided by direct observation; it must be 

 guessed at. Since the visited larva remains 

 intact, it is not prey that the Volucella's grub 

 is after. Besides, if murder formed part 

 of its plans, why dive to the bottom of the 

 cell, instead of attacking the defenceless re- 

 cluse straightway? It would be much easier 

 to suck the patient's juices through the actual 

 orifice of the cell. Instead of that, we see 

 a dip, always a dip and never any other 

 tactics. 



Then what is there behind the Wasp-grub? 

 Let us try to word all this as decently as 

 we can. In spite of its exceeding cleanli- 

 304 



