XXV INSECTA : HYMENOPTERA 395 



The wasps have stored no honey for food, and food is 

 getting scarce. They cease to feed the grubs, which till 

 now they have cared for so constantly, and, as if maddened 

 by their inability to do so, they are said to drag many of 

 them from their cells, carrying them out into the open and 

 leaving them to perish, whilst they themselves either wander 

 outside till the cold kills them, or return to the nest, and 

 there become torpid and soon die of cold and starvation, 

 their queen, the foundress of the colony, dying with them. 



Probably in Wasps, as in Bees, the most sensi- 

 of Wam^^ tive organs of the body are those special organs of 

 Unuih, the antennae, which are used as the means of 

 communication between one individual and another. Here, 

 as in bees, these organs are kept scrupulously clean by means 

 of a "brush and comb" structure on the front leg, through 

 which they are frequently drawn. The sense of sight seems 

 to be good. There are the usual large compound eyes, which 

 are kidney-shaped, and also three ocelli ; it is not yet known 

 with any certainty how these different eyes function. Wasps, 

 when they first leave their nest, fly round and above it, as 

 if to fix a picture of it in their minds, and then they fly 

 straight off to their destination, taking short journeys at first 

 and gradually extending them. 



If, whilst they are out, we take the opportunity of cover- 

 ing the ground round their nest with a square of coloured 

 paper, leaving a hole just over the entrance to it, they will on 

 their return appear greatly disturbed. They will hover around, 

 and hundreds may collect outside, afraid to go in, until at last 

 one enterprising spirit makes the venture and comes out again 

 unharmed, whereupon the rest are reassured and gradually 

 follow the example of the pioneer. In a few days they have 

 got so accustomed to the paper that its removal, and the 

 consequent reappearance of the natural surroundings of the 

 nest, gives them cause for fresh alarm. Testing them with 

 different colours gives indications of a distinct preference on 

 their part for some colours over others — green seems to be 

 liked best, and then perhaps purple, i 



The sense of hearing does not seem acute, at any rate with 

 respect to the sounds which usually affect us. Some agitation 



' These statements are based on the interesting experiments performed by 

 Miss C. Isaacson. 



