55 
application of arsenical mixtures and the further fact that nearly all 
feeding is done upon the under side of the leaves. The arsenicals, 
however, seem to be our best means of destroying the beetles by 
means of insecticides. 
Phytoptus sp.—There is a Phytoptus mite that seems to be steadily 
on the increase in Colorado, which attacks the cottonwoods. As the 
leaves open in the spring, reddish excrescences begin to form about 
the buds and upon twigs and limbs, of a more or less reddish color, 
that continue to enlarge in size during the summer. The year follow- 
ing, additional growth may appear about the old gall and new ones 
form. In early spring the mites within the chambers of the galis are 
of a deep red color, while those that appear during the summer are 
lighter in color. Inthe northern portion of the State these galls are se 
abundant as to be very noticeable to passers-by when the foliage is 
off. Some trees are literally filled with them, so that scarcely a twig 
can be found without one or more of the galls upon it. 
Another peculiar development, as the result of Phytoptus attack in 
the cottonwoods, takes place in the same trees, and may be due to the 
Same species, so far as I know. It is the transformation of the flower 
catkins into large pendant masses, often 6 or 8 inches in length, remind- 
ing one of a long slender cluster of grapes. An interesting thing in 
connection with this abnormal growth is that the attack of the mites 
causes the flower parts to revert into leafy growths, pointing to the 
origin of the development of the parts of the flower. 
LEAF-CUTTER BEES. 
Until the present summer I have never heard of leaf-cutter bees 
being abundant enough to seriously defoliate plants, but am told by 
an intelligent lady residing near Fort Collins, some 10 miles from the 
foothills, that her rosebushes were so badly defoliated by them the 
past summer that it was necessary to cover them during the day to 
Save any leaves at all. 
Mr. Caudell said that in the garden of W. M. Rysler, of Delta, Colo., 
this season he saw a number of mature radishes, every plant of which 
was completely killed by the minute false chinch bug (Nysiws minutus 
Uhler), myriads of which at that time covered the entire plants. In 
some gardens he saw a patch of potatoes much injured by the larvee of 
Plusia brassice. The injury was so striking as to be noticeable from 
a distance, resembling the ravages of the potato beetle. These same 
larvee were infesting cabbage, cauliflower, lettuce, sugar beets, and 
garden beets. 
Mr. Hopkins said that he had collected the galls of a Chermes sp. 
(which Mr. Pergande thinks may be Chermes sibiricus) from the Sitka 
