Saw-flies, Gall-flies, Ichneumons, etc. 505 
few days issue as winged wasps. They are exclusively workers. These 
Fig. 709 .—Vespa sp. a, worker; b, female or queen. (After Jordan and Kellogg; 
natural size.) 
workers now enlarge the nest, adding more brood-cells in which the 
queen deposits eggs. The bringing of 
food and care of the young now devolve 
on the workers. The new or second 
brood is also composed of workers only, 
and these immediately reinforce the first 
brood in the work of enlarging the nest 
and building new brood-cells. Thus J. ; fV 
through the summer several broods of Fig. 710.—Two workers of the yel- 
workers are reared, until in the late sum- low-jacket, Vespa sp. (From life; 
. r „ . , . . . natural size.) 
mer or early fall a brood containing males 
and females as well as workers appears. The 
community is now at its maximum both as re¬ 
gards population and size of nest. In the species 
(Vespa sp.) which make the great ball-like aerial 
nests the community may grow to number 
several thousand individuals. The males and 
females mate (presumably with members of 
other communities), but no more eggs are laid, 
and with the gradual coming on of winter the 
males and workers and many of the females die. 
There persist only as survivors of each com¬ 
munity a few fertilized females; these crawl 
into safe places to pass the winter. Any 
social wasp found in winter-time is thus, almost 
certainly, a queen. Those of the queens which 
Fig. 711.—Communal nest of come safel y throu g h the Ion S winter found 
the yellow-jacket, Vespa sp. the communities which live through the follow¬ 
ing season. 
(Much reduced.) 
The social wasps of the genus Vespa, the familiar yellow-jackets and 
