36 MISC. PUBLICATION 318, U. S. DEPT. OF AGRICULTURE 
liquid foods such as the nectar of flowers. The honeybee (Apis melli- 
jera) spends the winter in the adult stage in the hive. The life 
changes are complete. 
Bumblebees.—What farm or small-town boy or girl has not had 
the experience of fighting a nest of bumblebees? It is doubtful if 
any of these boys or girls realized 
that bumblebees are beneficial insects 
and necessary to the pollination of 
certain flowers, especially the clovers. 
Bumblebees are so well known that 
little description is necessary. How- 
ever, it should be stated that they are 
about five-eighths of an inch long, 
have four wings, belong to the order 
Hymenoptera, and have mouth parts 
modified for chewing and sucking. 
The adults feed on flowers. It is at 
the time of feeding as well as of gathering nectar and pollen, upon 
which they rear their young, that they pollinate the flowers. Bumble- 
bees have complete life changes and overwinter as adult queens in 
sheltered crevices or cavities. The one shown here, Bombus ameri- 
canorum, 1s sometimes called the black- 
tailed, yellow-banded bumblebee. 
Pigeon tremex.—The pigeon horn- 
tail (Tremex columba) is one of our 
largest Hymenoptera. It may grow to 
be 114 inches in length, exclusive of its 
egg-laying appendages. It is black, 
with ocher-yellow markings, the pro- 
portionate amounts of yellow varying. 
The mouth parts are modified for chew- 
ing and lapping. The larva of this 
insect bores into the dying branches 
or trunks of trees such as maple, elm, 
apple, pear, beech, oak, and sycamore, and apparently spends 
the winter as a full-grown larva or pupa in the trunks of these trees. 
This insect, like all other Hymenoptera, has complete life changes. 
Infestations may be prevented by keeping trees in a vigorous grow- 
ing condition. In case of heavy infestation, trees may be cut and 
burned during the fall and winter, thereby 
destroying the larva. 
Chalcid flies —If it were not for our 
friends in the insect world, certain pests 
would make our existence difficult. Some 
of these friends of ours are very tiny and 
frequently unnoticed; for example, the 
chalcid flies. Some species are parasitic 
and live inside various other insects. All 
chalcid flies belong to the order Hymenoptera. They have four 
wings, chewing mouth parts, and complete life changes. The species 
FIGURE 90.—Bumblebee. 
FIGURE 91.—Pigeon tremex. 
FIGURE 92.—Chalcid fly. 
