5 
B. Scale flattened, but comparatively large, diameter 3mm., or nearly; exuvice form- 
ing a slight prominence between the middle and the side, when rubbed so 
as to remove a thin film of secretion, appearing shining orange or foxy-red. 
1. Scale grayish-brown..............---....-...A. juglans-regiw Comst. 
ASC al Ou WINL Oy arcae see coer wal eas Sinica Sieveicisie ee oa a 1. juglans-regiav v. albus Ck, 
C. Scale flattened like the last, but smaller; diameter 2mm. or less. 
1. Seale pale grayish, with a slight reddish tinge, the male scales suffused with 
blackish, exuvie of the 9 scale somewhat to the side of the center, dull 
OTA Cees oe sere Oe aie etoee ses ict emia Sa Se se ciseeae eee tine oe 4. howardi Ckll. 
2. Scale blackish or dark gray to dull black, the exuvire when exposed a deep 
orange-red, their position somewhat away from the center. 
a. Seale usually very dark, first skin hardly raised or nipple-like; a species 
common in the transition zone, often on maples... .... A. ancylus Putn, 
b. Seale somewhat paler, first skin somewhat raised and nipple-like, with 
faint indications of a dot and ring ..-....----...--...A. forbesi Johns. 
3. Seale of female gray, with the exuvi:e central, or nearly so, yellowish, ¢ 
scales showing a distinct dot surrounded by a ring, which is not the case 
in A. howardi. 
a. ¢ scale all black, the dot and ring not distinguished by color, but dis- 
tinctly sculptured; a Japanese species. .....A. andromelas Ck1l. n. sp. 
b. ¢ seale grayish, hardly black, with a light dot and ring. 
A, perniciosus Comst. (San José seale). 
ce. g scale grayish black, the light dot and ring very conspicuous; occurs 
on orange and plum in Japan...--.. 4. perniciosus v. albopunctatus Ckll. 
The seale of A. cydonie Comst., found on quince in Florida, resembles 
that of rapar. A. crawiti Ckll. n. sp., a Mexican species, has also a con- 
vex scale, but the exuvice are not dark. The European A. ostreeformis 
Curt. has a black scale with deep orange exuviie, and could easily be 
taken for ancylus. 
It has been a matter for dispute whether the San Jose scale can be 
certainly recognized in the field. Its effect on the tree, killing the 
branches, is characteristic, but hardly in any true sense diagnostic; 
while the reddening of the tissues of the plant adjacent to the scale is 
sometimes well marked with A. ancylus as well as with perniciosus. A 
little experience, ho-vever, enables one to recognize the ashy-gray, gen- 
erally thickly massed scales of periiciosus, with the dot and ring of the 
male scale; as against the dark scale and contrasting reddish-orange 
exuvie of ancylus, or the similar scales of ostrevformis and forbesi. Nor 
will the very pale scale of howardi, found singly on plums, be likely to 
cause confusion. At the same time it is to be recommended that the 
diagnosis made in the field be in every case confirmed by examination 
of the insect under the compound microscope, if either locality or plant 
is new. 
A. forbesi was only recently described from Illinois, but I have this 
year found it on apple trees in Mesilla, N. Mex , and it will probably 
be detected in other parts of America if looked for. 
THE MICROSCOPICAL CHARACTERS OF THE ADULT FEMALE. 
The female insect should be carefully removed from beneath the 
scale and boiled for a moment in strong liquor potasse. It will then 
be transparent, and can be examined witha compound microscope. It 
