BUREAU OF ENTOMOLOGY AXD PLANT QUARANTINE 59 
the past 8 years in cooperation with the Tobacco Section of the Bio- 
chemical Division. Eastern Regional Research Laboratory of the Bu- 
reau of Agricultural and Industrial Chemistry. 
Insect Cholinesterase Found To Differ From Human Enzyme 
The action of the enzyme cholinesterase is inhibited by parathion 
and other organic phosphates. Continuing studies showed that this 
enzyme from the heads of house flies, honey bees, and cockroaches 
differs not only in each insect species but also from that in vertebrates. 
HONEY BEES AND OTHER POLLINATING INSECTS 
Crop Producers Recognize Their Dependence on Bees 
Producers of legume seeds in the West are beginning to realize 
their dependence on bees and other pollinating insects as did eastern 
fruit growers some 30 years ago. This is evidenced by the fact that 
they now seek bees and, contrary to their practice in the past, are 
willing to pay the beekeeper a cash rental or give him a share in the 
seed crop for the use of his bees. 
Bees still remain in short supply for pollinating purposes. The 
situation is aggravated by the fact that beekeepers in increasing num- 
bers are going out of business or reducing their holdings because of 
their inability to operate at a sufficient profit at present prices. 
Bees Essential in Cantaloup Production 
The need of honey bees for the pollination of cantaloups in Arizona 
was established by held observations and by cage tests. During 2 
days in which the visits of all insect visitors to marked cantaloup 
flowers in an open field were recorded, 586 honey bees and 4 native 
bees visited the flowers. In plots caged to exclude honey bees, only 
4 marketable melons were obtained from 160 plants. In caged plots 
of the same size in which bees were confined, 180 marketable melons 
were produced. Caged plots supplied with an abundance of honey 
bees gave an estimated 30-percent higher yield than open plots left 
to be pollinated under prevailing commercial conditions. 
The studies were made in cooperation with State and local agen- 
cies, with funds authorized under the Research and Marketing Act. 
Breeding Queen Bees Distributed 
In the bee-breeding project being conducted on Kelleys Island in 
Lake Erie, in cooperation with The Honey Bee Improvement Coop- 
erative Association, 1,225 hybrid queens were sent to cooperators for 
test purposes. 
Bees in Abundance Needed for High Yield of Red Clover Seed 
Yields of red clover seed in 1950 from experimental plots in Ohio 
pollinated by honey bees ranged from 6.2 bushels to 10.6 bushels an 
acre. Best yields were obtained from open field plots provided with 
four colonies of honey bees an acre. The number of pollination visits 
