THE SAN JOSE SCALE AND ITS NEAREST ALLIES. 
By T. 1). A.. COCKERELL. 
THE PRELIMINARY EXAMINATION. 
Suppose that some objects suspected to be San Jose scales have 
been found upon a fruit tree. The hist thing to do is to ascertain 
whether they are scales (Coccidfe) at all. I have known fly marks to 
be taken for Ooccidae, and occasionally the lenticels on the young 
growth of trees are supposed to be scale insects by those whose experi- 
ence ought to have taught them better. It is really remarkable how 
the lenticels on cotton wood twigs in the Mesilla Valley, N. Mex., resem- 
ble a scale prevalent in that locality, Aspidiotus jvglans-regice var. albus. 
From a short distance the deception would be complete but for the 
fact that the lenticels are arranged at approximately equal distances 
from one another and not massed like scale insects. Still more like 
coccids are certain fungi; I have on occasion been obliged to use a 
lens to ascertain which I had before me. At Mesilla, N. Mex., I found 
on the dead wood of an apple tree a fungus which closely resembled the 
second stage, or immature male scales of the Sau Jose scale. This 
fungus was kindly identified for me by Mr. J. B. Ellis as the cytispora 
stage of Valsa ambiens Persoon. It is presumed that no entomologist 
will be misled for more than a moment by lenticels or fungi, but for 
those who are not entomologists it may be recommended to scrape the 
object with the linger nail or a knife blade, when, if it is a scale insect, 
it will readily come away, leaving at most only a pale film. 
Granting now that we certainly have a scale insect before us, it is to 
be learned whether it belongs to the subfamily Diaspime. A mealybug 
has no scale — only some mealy or cottony secretion; a Lecanium or 
shield scale is itself the scale — that is, the insect becomes hardened and 
scale like, but has no scale separable from its body. But the Diaspime 
are small soft insects, in the adult $ stage without legs and unable 
to move, which secrete a scale separate from themselves, much like the 
shell of an oyster. With a lens it is easy to make out the insect and 
its scale, the latter having first been overturned with the point of a 
knife. The scale, it is further seen, carries the exuvia) of the two first 
stages, or only one if it be a male. 
Now, then, if we are sure that w r e have a Diaspine is it an Aspidiotus — 
the genus of the San Jose scale? In Aspidiotus the female scales are 
round, or nearly so, and the male scales vary from round to oval, 
according to the species, but are always of a similar texture to those of 
the female. Therefore we shall not be misled by Mijtilaspis, in which 
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