174 
JOURNAL OF ECONOMIC ENTOMOLOGY 
[Yol. 13 
ash and lilac to apple failed, evidently for the reason that it could not 
live on apple. Observations made throughout the Twin Cities dis¬ 
closed the fact that apple trees though standing in such close prox¬ 
imity to heavily infested ash, poplar and lilac that their branches 
touched were free from scale; and, furthermore, pear, peach, plum, 
hackberry and horse-chestnut, all of which are listed as host plants of 
Lepidosaphes ulmi, standing in the same situations were likewise free. 
A closer examination of specimens taken from apple, poplar, ash, 
willow, lilac, cornus and Rosa rugosa brought to light two distinct 
forms of the scale, and a third form which differs in some particulars 
from that which infests apple. For the purpose of this paper we shall 
designate them as the brown form, the grayish-brown, or banded 
form, and the yellowish-brown form. 
The brown form is the one which infests apple. It appears to be 
identical with the European species, Lepidosaphes ulmi Linnaeus. It 
has been successfully transferred to lilac, ash and cornus. An attempt 
to transfer it to poplar was unsuccessful, but the failure may have 
been due to the small number of young insects used in the experiment. 
The shade of color of the scale itself varies somewhat on different 
kinds of bark, but it is a uniform brown. In immature specimens the 
part of the scale developed after the first molt is darker than the exuvia. 
Specimens of old scale which have been exposed to the weather are 
very dark, nearly black. This scale is double-brooded, the first brood 
hatching during the first or second week in May at Urbana, the second 
brood during the latter part of July. This form is usually very heavily 
parasitized. 
The gravish-brown scale is the one that is generally and destruc¬ 
tively abundant on poplar, ash, willow, lilac, cornus, and Rosa rugosa 
in Urbana and Champaign, and at numerous other places in the 
northern half of the state. American elm, soft and hard maple, 
ailanthus and linden growing near heavily infested ash and poplar 
may become infested and be seriously injured by the large number of 
young which are carried to them annually from the infested trees, but 
in other situations they do not become infested, and it is doubtful 
whether the scale can maintain itself on them. It cannot live on 
apple, pear, peach, plum, hackberry and horse-chestnut. 
The prevailing color of this scale is brown, but there are more or 
less distinct transverse grayish bands, one just behind the first exuvia, 
another near the middle of the scale, and a third at the posterior 
margin. These bands are sufficiently distinct and constant to serve 
as a means of distinguishing this form from the other two. 
Old scales when exposed to the weather become a bluish-white. In 
immature specimens the part of the scale formed, after the first molt, 
