28 HYMENOPTERA CHAP. 



purpose five or six loads of pollen are brought to the cell, each 

 load being, as we have already remarked, about half the weight 

 of the Insect. This material is then formed into a ball and made 

 damp with honey ; then another load of pollen is brought, is 

 mixed with honey and added as an outer layer to the ball, which 

 is now remodelled and provided on one side with three short feet, 

 after which an egg is placed on the top of the mass ; the bee 

 then sets to work to make a second chamber, and uses the 

 material resulting from the excavation of this to close completely 

 the first chamber. The other chambers are subsequently formed 

 in a similar manner, and then the burrow itself is filled up. 

 While engaged in ascertaining these facts, Mliller also made 

 some observations on the way the bee acts when disturbed 

 in its operations, and his observations on this point show 

 a very similar instinct to that displayed by Chalicodoma, 

 referred to on a subsequent page. If interrupted while storing a 

 chamber the Insect will not attempt to make a fresh one, but 

 will carry its stock of provisions to the nest of some other 

 individual. The result of this proceeding is a struggle between 

 the two bees, from which it is satisfactory to learn that the 

 rightful proprietor always comes out victorious. The egg placed 

 on the pollen-ball in the chamber hatches in a few days, giving 

 birth to a delicate white larva of curved form. This creature 

 embraces the pollen-ball so far as its small size will enable it to 

 do so, and eats the food layer by layer so as to preserve its 

 circular form. The larva when hatched has no anal orifice 

 and voids no excrement, so that its food is not polluted ; a 

 proper moulting apparently does not take place, for though a 

 new delicate skin may be found beneath the old one this latter is 

 not definitely cast off. When the food, which was at first 100 

 to 140 times larger than the egg or young larva, is all consumed 

 the creature then for the first time voids its refuse. During 

 its growth the larva becomes red and increases in weight from '0025 

 grains to '26 or '35 grains, but during the subsequent period of 

 excretion it diminishes to '09 or "15 grains, and in the course of 

 doing so becomes a grub without power of movement, and of a 

 white instead of a red colour. After this the larva reposes 

 motionless for many months in fact, until the next summer, when 

 it throws off the larval skin and appears as a pupa. The larval 

 skin thus cast off contrasts greatly with the previous delicate condi- 



