36 



MISC. PUBLICATION 318, U. S. DEPT. OF AGRICULTURE 



Figure 90. — Bumblebee. 



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liquid foods such as the nectar of flowers. The honeybee (Apis melli- 

 fera) 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, Borribm ameri- 



canorum, is 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 l 1 /^ 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 91. — Pigeon tremex. 



Figure 92. — Chalcid fly. 



