3 20 POPULAR SCIENCE MONTHLY. 



the hollows of trees and logs, which they occasionally clean out 

 to render the places fit for their purposes. 



Arthur Shipley, in describing some of the habits of the Ves- 

 pidm, has said in part that the workers among hornets " are 

 females in which the ovary remains undeveloped ; they resemble 

 the perfect female in external appearance, but are slightly 

 smaller. Unlike the bees', the wasps' community is annual, 

 existing for one summer only. Most of the members die at the 

 approach of autumn, but a few females which have been ferti- 

 lized hibernate through the winter, sheltered under stones or hol- 

 low trees. In the spring and with the returning of warm weather 

 the female regains her activity and emerges from her hiding 

 place. She then sets about finding a convenient place for build- 

 ing a nest and establishing a new colony." 



The methods of making the paper cells and their arrangement, 

 the laying of the eggs in them, and the rearing of the young are 

 practically much the same in both the common wasps and the 

 social paper hornets. So Professor Shipley, after describing the 

 manufacture of the paper nest of the common wasp ( Vespa vul- 

 garis) how she lays a single egg at the bottom of each of the 

 first three cells, and then this, the foundress of the society, " con- 

 tinues to add cells to the comb, and as soon as the grubs appear 

 from the first-laid eggs she has in addition to tend and feed them/' 



" The grubs are apodal, thicker at the middle than at either 

 end ; the mandibles bear three teeth ; the maxillae and labium are 

 represented by fleshy tubercles. The body, including the head, 

 consists of fourteen segments, which bear lateral tubercles and 

 spiracles. They have no arms. They are suspended with the head 

 downward in the cells, and require a good deal of attention, being 

 fed by their mother upon insects which are well chewed before 

 they are given to the larvae, or upon honey. At the same time 

 the mother is enlarging and deepening the cells in which they 

 live, bHiilding new cells and laying more eggs, which are usually 

 suspended in the same angle of each cell. The development 

 within the egg takes eight days. 



" After about a fortnight the grubs cease to feed, and, forming 

 a silky cover to their cells, become pupae. This quiescent state 

 lasts about ten days, at the end of which period they emerge as 

 the imago or perfect insect. The silky covering of the cell is 

 round or convex outward, and to leave the cell the insect either 

 pushes it out, when it opens like a box lid, or gnaws a round hole 

 through it. As soon as the cell is vacated it is cleaned out and 

 another egg deposited. In this way two or three larvae occupy 

 successively the same cell during the summer. The first wasps 

 that appear in a nest are neuters or workers, and these at once 

 set to work to enlarge the comb and feed the larvae, etc. . . . 



