32 the coeorado experiment station 
siderable numbers upon individual trees in some of the orchards 
of the Grand Valley last year. It attacks the leaves, causing 
them to curl exactly as in the case of the green apple aphis, but 
it is readily distinguished from that species by the pink color, espec¬ 
ially of the wingless forms, and by the slight covering of a white 
powdery material. The winged lice have their head and thorax 
nearly black, but the abdomen is yellowish or rusty brown about 
the margins and dark brown over the middle portion, and never 
green or black as in the other species mentioned upon the apple. 
We are calling this, rather doubtfully. Aphis pyri Boyer. Remedies 
the same as for the green apple aphis {Aphis pomi). 
THE SWEET CLOVER APHIS 
{Aphis medicaginis Koch.) 
This small black plant louse, while having a decided preference 
for certain legumes, as the sweet clovers, the locos, black locust, 
and wild Licuorice {Glycyrrhiza lepidota), feeds to some extent 
upon a very wide range of plants. We have frequently found it 
upon tender new shoots of apple and other fruit trees early in the 
season, and have received inquiries concerning it. 
The wingless lice, when fully grown, are very deep shining 
black. Other wingless individuals of the colony are dark green to 
slaty gray but not black. From these colors alone the orchardist 
will be able to distinguish this from other species attacking the 
apple. Whether the colonies of this louse upon the apple came from 
stem-mothers hatching from over winter eggs has not been deter¬ 
mined. We have never seen the eggs or true sexual forms of this 
species anywhere. It is not likely that this louse will ever become 
a serious orchard pest. 
PEACH PLANT LICE 
THE GREEN PEACH APHIS 
{Myizus persicae Sulz.) 
Plate II, Figs. 5 to II. 
This is by far the most abundant peach louse in Colorado. 
It seems to have been brought to this country from Europe where 
it was first described by Sulzer as a peach insect in 1761. Forty 
years later Shrank, finding it upon Diantlms (the pink) gave it 
the specific name dianthi. Koch in Germany redescribed it under 
zation of malifolii, as given by Fitch. So we are calling our rosy apple 
aphis Aphis pyri Boyer, until we get further llight upon the subject. 
It might be added that the Aphis sorbi described by Buckton, Vol. II, 
p. 83, and which is referred itio by Schouteden as this species in his paper 
(“C^italogue des Aphides de Belgique,” p. 228), in “Memoires de la Soc. 
Entom;. de Belgique, T. XII,” is not sorbi unless both the descriptions and 
the Illustrations are very incorrect, and the specimens we have from Dr. 
Cholodkovsky incorrectly determined. 
