THE OYSTER-SHELL SCALE. 
(Lepidosaphes ulmi L.) 
ORIGIN AND DISTRIBUTION. 
The origin of the oyster-shell scale is a matter of some uncertainty. 
It has a world-wide distribution, and was introduced into the New 
England colonies at an early date. The first American account of this 
pest was written by Enoch Perley in 1794, in which he stated that it 
was doing considerable damage to the apple in Cumberland County, 
Maine. In the early sixties it had reached the Mississippi River, and 
at the present writing (April, 1910) occurs in every State of the Union 
with the possible exception of South Dakota, Oklahoma, and Texas. 
Its occurrence in these States is practically certain, but there appear 
to be no records in literature to this effect, and it has not been received 
from these States by the Bureau of Entomology. The insect is very 
t mublesome in the Northern States and is especially common in the 
New England States and those bordering the Great Lakes. 
DESCRIPTION AND LIFE HISTORY. 
This insect has received the common name "oyster-shell scale," 
owing to the resemblance of its scale or covering to a long, narrow 
oyster shell, as may be seen by reference to figure 1. The adult 
female scales are about one-eighth of an inch in length, usually brown 
to dark brown in color, though occasionally they have a grayish 
appearance which is due to bleaching over winter. If present in 
large numbers, for want of room they assume various more or less 
curved shapes. The scale of the male in shape and color resembles 
that of the female, but is smaller and possesses at the posterior 
extremity a small hinge or flap which permits the exit of the adult 
male. 
If during winter or early spring one of the female scales be removed, 
numerous small, oval, white eggs varying in number from 40 to 100 
will be revealed, and at the anterior portion can be seen the dead and 
shriveled body of the female. 
In Canada and the Northern States there is thought to be but one 
full brood annually, whereas in the Middle and Southern States the 
species is double brooded. 
The following records from literature and from the Bureau of Ento- 
mology will indicate the time in the spring of hatching of the eggs of 
this insect, in various localities. This time will, of course, vary with 
the season, but, in general, as long ago stated by Doctor Mygatt, in 
Illinois, will for any locality be shortly after the time of the falling 
of the blossoms of the apple. 
[Clr. 121] 
