INJURIOUS INSECTS OF I909Q AND IQIO. I29 
a wooden frame, covered with white cheese-cloth on three sides 
and on the top. A loose glass plate forms the fourth side. The 
floor is of wood, perforated in the center in such a wav as to allow 
cloverheads from two or more plants to be introduced into the 
cage. The apparatus is suspended over the growing plants. The 
perforations through which the clover-heads are introduced can be 
shut to exclude other insects, and to keep the clover-stems in place, 
by means of two wooden shutters. 
The method of procedure in 
securing the cross-pollination of 
the florets has been to confine 
the green heads in other cages, 
made of mica lamp-chimneys, 
closed at the top with a piece of 
cheese-cloth and at the bottom 
with a fold of the same kind of 
cloth, which can be firmly tied 
around the stem bearing the in- 
troduced head. This cage is 
held in place above a plant by a 
cord from above and_ below. 
The latter apparatus was sug- 
sested in an article by C. E. 
Hood in the April, 1909, num- 
ber of the Journal of Economic 
Entomology. Of course these 
heads might have been covered 
mriLueucese-croin, Hues, Dib ath, tele. Smee. ene: | suscessty 
that case they could not have 
been so easily watched. When 
the florets open and are ready for pollination, they are removed 
from the mica cages and introduced into the cage made by Mr. 
Urbahns, and described above. Into this cage one or two bumble- 
bees are introduced, and we found that early in the season the bees 
worked faithfully every day, after becoming accustomed to their 
prison, occasionally for as long as three weeks. Later in the sea- 
son their work was not quite so satisfactory, but when captured 
early in the morning they usually worked well for a few hours, 
after. which time they were liberated. When these clover-blossoms 
have been thoroughly gone over by the bees, they are removd from 
the pollinizing cage, and again placed in the mica cages for future 
