WASPS 207 



and sharply pointed. There is no posterior opening of the 

 digestive system, but the indigestible portions of the food accum- 

 ulate in the last portion of the gut and are removed with it at 

 the moulting of the skin. The larva, having reached its full 

 size, spins a silken cocoon which lines the inside of the cell and 

 covers the open end with a white projecting dome ; it then casts 

 its second skin, and becomes a pupa or chrysalis. The pupal 

 skin is very thin and transparent, and through it can be seen 

 the as yet soft body of the imago or perfect insect, with its legs, 

 wings, antennae, and other parts ; these organs are indeed present 

 in the pupa itself, but are not glued down to the sides of the body 

 as they are in the pupa of a moth or butterfly. No food is taken 

 during pupal life, but extensive alterations in the muscles and 

 other internal organs are effected at the expense of stores of 

 fat laid up within the body by the larva. After a few days the 

 imago is ready to emerge, and, casting off the pupal skin, she 

 attacks the dome-shaped end of the cocoon with her mandibles, 

 and bites her way out. For a short time her body is damp, 

 the colours dull and the wings soft, but in a few hours the final 

 vigorous condition is reached, and the " worker," for such she 

 is, is ready for duty. The length of time from the deposition 

 of the egg up to the emergence of the imago is about a month. 

 So soon as the " queen " has reared her first batch of workers 

 she forthwith abandons the task of building cells and collecting 

 food, but devotes the whole of her energies to the work of laying 

 eggs. Henceforth she never quits the nest, her worker offspring 

 relieving her of all other duties. The strength of the nest now 

 rapidly increases : the workers add further cells to round the 

 margin of the first comb until its diameter is some four or five 

 inches ; below this, and suspended from it by numerous pillars, 

 a second similar comb is added, and so on up to as many as ten 

 or twelve combs one below the other, if the season be favourably 

 hot. Meanwhile many additional coverings are added outside 

 those first made by the queen, layer upon layer until the wrappings 

 are perhaps an inch in thickness. The earlier and smaller cover- 

 ings are cut away as the circumference of the growing combs 

 spreads outwards, and their material is employed elsewhere. 

 The whole fabric of the nest is composed of wood-fibre worked 



