538 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION. 
apple, crab, and the European mountain ash (Sorbus aucuparia) in Illi- 
nois; and I have found it common in apple and pear in Xew York, 
Man land, and southern California, and upon black cherry in western 
New York. 
Although this insect has been well known for many years, compara- 
tively little has been written respecting it. This is probably due to the 
fact that there is another species {Mytilaspis pomorum Bouche) which, 
like this, infests the apple, and which is more common and much more 
destructive. The scurfy bark-louse was first described, but not named, 
by Earns in his " Insects Injurious to Vegetation" (Flint editiou, p. 254). 
In this description both the scale formed by the male and that formed 
by the female are well characterized; but the insects themselves were 
not studied by Dr. Harris. The description of the scales is remarkable 
as containing an explanation of their uature and probable mode of for- 
mation as follows : The minute oval dark colored scales on one of the 
ends of these white cases are the skins of the lice while they were in the 
young or larva state, and the white shells are probably formed in the 
same way as the down which exudes from the bodies of other bark lice, 
but which in these assume a regular shape, varying according to the sex 
and becoming membranous after it is formed." This statement must 
have been overlooked by Dr. Fitch, who mauy years afterwards, in his 
first report as State entomologist of Xew Y^ork, p. 739 (35), in writing 
of the oyster-shell bark louse of the apple, states that " these scales are 
the relics of the bodies of the gravid females, covering and protecting 
their eggs." And in his second report, p. 489 (257), Dr. Fitch, in describ- 
ing the pine-leaf scale (Mytilaspis pinifolice) states that the three parts 
of the scale represent seemingly the head, thorax, and abdomen of the 
living insect. 
Through the kindness of Mr. Lintner and the officers of the New 
York State Agricultural Society I have had the opportunity of studying 
the Coccidse in the collection of that society. The specimens were ail 
labeled by Dr. Fitch, and by a very careful study of both the scale and 
the last segment of the female, of the specimen labeled Aspidiotus cerasi, 
I have been unable to find any character which will separate it from the 
specimens labeled Aspidiotus furfurus, and all of these specimens belong 
to the same species as the very common pest of the apple and pear, which 
has been commonly known as Aspidiotus harrisii. 
The statement made by Sig noret* that this species is the same as that 
described by Curtis under the name of Aspidiotus (Diaspis) ostrecrfor- 
mis is evidently a mistake. M. Signoret has kindly sent me specimens 
of D. ostrewformis, from which I have prepared the description of that 
species in this report. 
Scale of female. — The scale of the female is flat, irregular in outline, many bending 
abruptly to the right or left immediately posterior to the second larval skin, others 
straight; in all the scale suddenly widens near the posterior end of the second larval 
*Annales de la Socie"t6 En torn, de France, 1876, p. 604. 
