- 7 - 
Metcalf, C. L., and Flint, W. P. 
1S28. Destructive and useful insects; their habits and control. 918 pp. 
New York. 
p. 264: Under farming conditions great changes take place in 
the character of the plants grown on the land. There are no longer 
a great number of species, generally intermixed, but a few species 
occupying the land in nearly pure stands of thousands and hundreds 
of thousands of acres. This affects the insect population of the 
land in two general ways. Many of those which depend on the plants 
of one family, or even on one species of plant, find their food supply 
: . off, except in the small uncultivated areas and may nearly, or 
quite, disappear from the region, as certain species of the bilibugs 
in drained bottom lands. 
Vansell, G. H. 
1342. Factors affecting the usefulness of honeybees in pollination. 
U.S. Dept. Agr. Cir. 650, 31 pp. 
p. 2: The orchards were located on top of a ridge, which was 
flanked on both sides by uncultivated lands, including both timber 
and manzanita-ceanothus brush. 
pp. 5-6: In the Camino district honeybees were the most common 
visitors to the blossoms, blowflies were next, and other insects \. 
scarce. a rule honeybees visit the blossoms of only one plant 
species on each field trip, while most other insects frequently shift 
from one species to another. For this reason no other insect compares 
favorably with the honeybee in pollen-distributing activity. Only 
honeybees and wild bees collected pollen for removal to their nests. 
Ants were surprisingly common in the orchard blossoms, feeding on nectar 
at temperatures well below that at which flying insects cease activity. 
Ants were observed -working in early morning, late evening, and during 
cold rainy periods, but probably they do not often move from tree to 
tree. Pollen seemed to offer no special attraction to them, but 
nectar and possibly sap did, because frequently these ants were engaged 
in taking nectar and in biting into tender twigs and the tiny fruit 
before the petals had fallen away. 
Bumblebees worked in the orchards during periods far too cold 
for the honeybee, Andrenids and other small bees were very sensitive 
to wind movement; they hung to leeward, and as a breeze increased 
to a gentle wind they disappeared. Honeybees were only slightly 
affected by a breeze of sufficient velocity to stop the andrenids. 
Wild bees were more in evidence near uncultivated lands. Blowflies 
were extremely active on pear blossoms, particularly for several 
hours before a rain. They also appeared on the sunny sides of tree 
trunks and limbs, and fed freely upon the fluid oozing from blight 
infections, where no honeybees were found. Syrphid flies eviden 
fed more or less on the pollen, but the chief interest of flies in 
general was in nectar. 
