BUREAU OF ENTOMOLOGY AND PLANT QUARANTINE 49 
Different species of wild bees seem to favor different crops. In 
Oregon the species of bumble bees that visited red clover were not 
found on Ladino clover. The bumble bees common on red clover 
belonged to only 4 or 5 species out of about 30 found in the State. In 
one area surrounded by rocky hills, bumble bees were as abundant as 
honey bees on Ladino clover, whereas in more intensely cultivated areas 
no bumble bees were found on this clover. 
Wild Pollinating Insects Reared in Artificial Nests 
Although the importance of the bumble bee and other wild pollinat- 
ing insects has long been recognized, little has been done to rear and 
use them under controlled conditions. Experiments with bumble bees 
have given the most promise thus far. Of 54 artificial nests set out to 
attract bumble bee queens, 18 were found and accepted by young 
queens. In six of the accepted nests, males and new queens Avere pro- 
duced. Colonies of Bombus huntii Greene were the largest. In the 
most populous of these nests 455 worker and male cells plus 156 queen 
cells were found at the end of the season. 
Shade, concealment, and good drainage appear to be favorable fac- 
tors for nest location. It is not necessary to place artificial nests 
underground, even for species that usually nest there. Attempts to 
induce Megachile bees to nest in holes drilled in wooden slabs were 
unsuccessful, as were attempts to transplant Norma m-elanderi Ckll. 
into an artificial soil environment. 
Hybrid Queens Distributed for Testing 
Now that the artificial insemination of honey bee queens is proving 
satisfactory, beekeepers are showing much interest in the possibility 
of having hybrid bees that will prove as valuable to them as hybrid 
corn has proved to corn growers. This interest was greatly stimu- 
lated during the year when the Bureau, in cooperation with the Honey 
Bee Improvement Cooperative Association, began rearing and dis- 
tributing hybrid queens for testing purposes. About 1,200 queens 
representing crosses of selected lines were distributed to beekeepers 
in various parts of the country. The program for 1949 called for 
the distribution of about 2,500 queens, to be furnished in lots of not 
less than 25 to any one beekeeper at a price above the market and with 
the provision that the Government be furnished certain reports of 
their performance. Such queens are being reared and mated naturally 
at an isolated mating station on Kelley's Island in Lake Erie. 
New Insecticides Kill Only Field Bees 
The bees that actually visit the dusted field are the only members 
of a honey bee colony that are affected by certain new insecticides 
applied for the control of insect pests. In studies to determine the 
effect of some of the new insecticides when applied for insect control, 
the only bees killed were those visiting the field within 2 days after 
the application. Parathion killed 40 percent of the visitors, DDT 
28 percent, and chlordane 23 percent. Toxaphene killed only 8 and 
