of the Nests of Gregarious Hymenoptera. 189 



an egg. The insect was very assiduous in her attentions to tlie 

 nest, and was quite unassisted in her work, none of Iier progeny 

 having yet passed the state of larvae. She appeared to be most 

 engaged in deepening the cells in the early part of the day. The 

 material made use of for this purpose was rotten wood, which I 

 constantly observed her collecting from a rotten wooden paling 

 which was so decayed as to have been completely reduced to 

 touchwood. On one occasion, when she liad returned with a 

 quantity of material, she was busily employed in the nest for nearly 

 an hour, during which time I was engaged in watching her pro- 

 ceedings. She first passed her head into each of the cells that 

 contained the largest larvae, as if to feed them, and then, having 

 examined the others, began to increase the depth of the two outer- 

 most cells by applying new material to their edges. Finding the 

 comb unsteady on its pedicle, she passed to the top of the nest, 

 and was hidden from view for a long time, occupied, as I sus- 

 pected, from the subsequent greater steadiness of the comb, in 

 strengthening the pedicle. When she had been thus employed for 

 about twenty minutes, she returned to the surface of the comb, 

 and was engaged for a much greater length of time in deepening 

 the two or three outer cells, to the extent of at least a line each, 

 which was effected by the addition of the masticated wood reduced 

 to a pulp, and a])plied in thin layers to the edges of the cells. 

 When she had finished these she began to work in a similar 

 manner upon the edges of the outer covering of the nest, adding 

 layer after layer, but more irregularly, and of coarser materials, 

 so that her mode of proceeding was particularly evident in this 

 structure. On the followinfj morning at ten o'clock the cells had 

 been still further enlarged. A larva had also been hatched in 

 one of the outer cells during the night, and in the course of the 

 day three new cells were commenced. On the morning of the 

 28th the number of cells had been increased to thirty-two, and the 

 old ones had been much deepened. The larvje in the middle cells 

 were now more than treble their size when I first saw them, and 

 afforded me an opportunity of observing the manner in which they 

 maintain themselves in their cells ; which are suspended vertically, 

 with the open mouths downwards. They do this by a constant 

 vermicular or turning motion of the body, so that each larva is 

 incessantly changing its position in the cell. When this motion 

 has carried it towards the entrance or mouth of the cell, the larva 

 makes a sudden longitudinal contraction of its whole body, by 

 means of which it is carried backwards and upwards, and thus 

 regains its position at the base of the cell, from which its constant 

 VOL. in. p 



