98 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION. 
44. The WHITE-LINED TREE hopper. 
Thelia univittata Harris. 
Order Hemip i Hi ; family Mkmhracid.E. 
Common upon oak limbs ami twigs, puncturing them and Booking their juices. 
This tree hopper is found on the oak in July. It is about four-tenths 
of an inch in length : the thorax is brown, has a short, obtuse horn ex- 
tending obliquely upwards from in front, and there is a white line on 
the back extending from the top of the horn to the hinder extremity* 
| Harris.) 
4.">. '1 BE OAK BLIGHT. 
Erio8oma querd Fitch. 
Order Hemipteha ; family Aphidid^e. 
A species of blight, or a woolly aphis upon oak limbs, puncturing them and exhaust- 
ing them of their sap. 
This blight is very like a similar insect upon the basswood. The 
winged individuals are black throughout, and slightly dusted over with 
an ash-gray powder resembling mold. The fore wings are clear and 
glassy, with their stigma-spot dusky and feebly transparent, their rib- 
vein black, and their third oblique vein abortive nearly or quite to the 
fork. It is .16 long to the tips of its wings. (Fitch.) 
46. The white oak scale-insect. 
Lecanium quercifex Fitch. 
Order Hemiptera ; family Coccid.e. 
Adhering to the smooth bark of the limbs of the white oak, in June, an oval, con- 
vex, brownish-black scale, about .30 inch long and .18 wide, its margin paler and 
dull yellowish. (Fitch.) 
47. The quercitron scale-insect. 
Lecanium quercitronis Fitch. 
Order Hemiptera ; family Coccid^e. 
On the small limbs of the black oak; a scale like the preceding but smaller, and of 
a nearly hemispherical form; its color varying from brownish-black to dull reddish 
and pale, dull yellow, with a more or less distinct stripe of paler yellow along the 
middle of its back, aud the paler individuals usually mottled with black spots or 
stripes. Length, .20; width. .16 inch. (Fitch.) 
These scales are parasitized by Platygaster lecanii (Fitch) 
48. The black scale of California. 
Lecanium olew Bernard. 
The black scale is stated by Signoret to be properly in France an 
olive scale, sometimes, however, becomiug so common as to occur on all 
neighboring plants also. In California we find it infesting the greatest 
variety of plants and becoming a very serious enemy to orange and 
other citrus trees. I have found it at Los Angeles on orange and all 
