— 
19 
and he thinks the scale has been present in New York for thirty years 
or more. 
He states that ostreceformis, like ancylus, does not multiply or spread 
rapidly. The hatching period is later than that of the San Jose scale, 
and the species does not have as many broods as the latter, and is also 
apparently more parasitized. 
Aspidiotus ostreeformis winters in about the same stage of growth 
as tbe San Jose scale, namely, in the half-grown second stage. Matu- 
rity is reached about the end of June, judging from material received 
from Geneva, N. Y. In one lot fully one-half of the young had 
appeared by the 25th of June; and in another, hatching had just 
begun on the 30th of June. The species is ovoviviparous—that is, the 
young are fully developed within the mother female and escape from 
the inclosing amnion just before or at 
the moment of birth. 
To determine the number of broods, 
a lot of young, secured from material 
just mentioned, were colonized on a 
young pear tree in the insectary of the 
Department about July 1. This ex- 
periment came to naught, on account 
of the fact that all of the female scales 
and most of the male scales were 
parasitized before reaching maturity. 
The insect may be single brooded, at =! 
least in its northern range, but the Fig. 2.—Aspidiotus ostreeformis: a, young 
number of broods is still in doubt and _larva, from beneath, much enlarged; , an- 
is a matter which demands careful plveane Peet a vance fhe 
investigation. Irrespective of the 
number of broods, the insect is capable of very great multiplication, and 
even of causing the death of trees, as has been already stated. 
DESCRIPTION OF THE FEMALE AND MALE SCALES. 
Female scale.-—The fully formed scale of the adult female on smooth, 
clean bark, and where not too crowded, often reaches a diameter of 3 mm., 
and is not much elevated. It is circular, the exuvie central, and easily 
exposed by rubbing, or often is self-ruptured, showing the small orange- 
colored larval exuvia, as in A. ancylus, forbes, ete. The larval scale is 
yellowish-white, bleaching to a light grayish-white in older individuals, 
if it be not broken or rubbed off as noted. The scale secreted by the 
second stage is very dark gray, almost black, and has a diameter of 
about 1mm. The supplemental scale secreted by the adult female often 
enlarges the completed scale to treble the diameter of the scale of the 
second stage, and when clear and fresh is light yellowish-brown in color. 
The inverted scale exhibits the large orange-yellow exuvia of the second 
stage, appearing at the central part of the scale and nearly equaling 
