30 the COLORADO EXPERIMENT STATION 
these stem females begin in the second generation to get wings 
and by the middle of June nearly all have left the trees and gone 
back to the clovers,** though some remain on the apple all summer. 
In the fall, many of the lice continue upon the clovers, going down 
close to the ground as cold weather comes on, and if the winter is 
not very severe, many will survive and continue to live and increase 
upon these plants throughout the year. Mr. L. C. Bragg has car¬ 
ried this louse through the winter in the laboratory upon red clover 
' without trouble, but no eggs or egg-laying females were obtained. 
So far as our observations have gone, this louse ranks next 
to the green apple aphis {Ahpis pomi) in numbers as a leaf in¬ 
festing species of the apple. Mr. George P. Weldon reports it as 
having a tendency to accumulate in the apple blossoms, but we can 
hardly consider it a serious pest as yet in Colorado orchards. 
Remedies the same as for the green apple aphis except that the 
application to kill the stem-mothers should be applied earlier, fully 
a week before the leaf buds begin to open at all. 
THE EUROPEAN GRAIN APHIS 
{Aphis (Siphocoryne) avenae Fab.) 
This louse was found in a few apple orchards in the Grand 
Valley in 1907, and during the spring and early summer of 1908 it 
was observed in small numbers upon fruit spurs and succulent 
sprouts upon the trunks and large limbs of apple, pear and quince, 
in the orchards about Delta, Paonia, Montrose and Rockyford. 
Mr. Weldon reported it on apple at Montrose as late as June 18. 
In no case has it been found in sufficient numbers to do appreciable 
harm. In our experience the apple has been the preferred tree, 
and colonies upon the pear and quince have been rare. 
This louse is readily separated from any of the other species 
here mentioned by the alternating transverse stripes of light and 
of dark green that cross the body above, by the light colored corni¬ 
cles with black tips that are present in both young and adult 
forms, and by the very short second fork in the third transverse 
vein of the fore wing of the winged forms. It curls the leaves in 
a manner similar to the green apple aphis. Aphis pomi. 
This insect was first described in Europe by Fab., as a grain 
louse, and it was not until 1894 that Mr. Theodore Pergande* 
discovered that it also feeds upon the leaves of apple trees during 
a portion of the year. It is said to be the most abundant apple 
leaf aphis of the eastern states. 
** July 8, and ag'ain Aug. 16, '08, severali,colonies were found 'on apple 
abouitl Fort Collins. Mr. Weldon reported this louse on apple at Delta, Colo., 
July 12, ’08. 
* Bull. 44, D!iv. of Entomology, U. S. Dept, of Agr. 
