24 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 
paper on the Tineide infesting the apple trees at Ithaca, N. Y., 
gives an account of the insect with figures of moth, larva, and mines 
in apple leaf. A more extended account is given by Dr. C. M. Weed 
in the Fifteenth Report of the Illinois State Entomologist (1889), 
pages 45-50; and it is mentioned by Lugger in Minnesota Experiment — 
Station Bulletin 61 (1898), page 316, and later (1903), by Wash- 
burn, in Minnesota Bulletin 84, page 66. In Bulletin 180 of the ~ 
Michigan Experiment Station (1900), ee 125, and Special Bulletin | 
24 of the same institution (1904), page 22, the species is the subject — 
of short illustrated articles by Pettit; and it is also discussed by © 
Lowe in Bulletin No. 180 of the New York Agricultural Experiment | 
Station (1900), page 134. In 1906 brief mention is made by C. P. © 
Close of the occurrence of this species in central Delaware (Bul. 73, © 
Delaware College Agric. Exp. Station, p. 18), where it is said to have © 
been increasing for several years past. 
The above includes the important references to this species so far — 
as the writer has been able to determine.* 
DESCRIPTIVE. 
The mine.—The mines occur exclusively on the upper surface of | 
leaves, beginning at the point of deposition of the egg as a narrow, — 
often curved line, gradually or suddenly enlarging in isolated and | 
typical examples, and finally having the outline of a trumpet or 
mussel shell (see Pl. V). Completed mines vary much in shape and — 
size, but will average, perhaps, in the more typical examples one-half _ 
inch long by one-fourth inch wide. There is considerable irregu- 
larity in the feeding habits of the larve, and blotch mines are often — 
produced, the narrow linear portion being frequently more or less— 
obliterated. In many mines crescent-shaped patches of white cross 
the linear portion, extending often well into the body of the mine. 2 | 
Unless held to the light the mine is scarcely noticeable from the lower 2 | 
surface of apple leaf, but above the blistered epidermis varies in _ 
color from whitish to dark brown, and the spotted appearance of 
badly infested leaves is noticeable some distance from the trees. _ 
Injury is confined principally to the palisade layer of cells immedi- _ 
ately below the epidermis of the upper surface of the leaf. The posi- _ 
tion of the mine on the leaf is quite variable, but it does not usually | 
cross the larger veinlets, extending more or GS parallel with them. ie 
The egg—The eggs of Tischeria malifoliella are regularly ellip- _ 
{ical in outline, somewhat convex centrally, but flattened around the — 
mar rgin, which area is more or less wrinkled. When first laid they 
«Since this article was prepared this species has been well treated by Mr 
C. D. Jarvis, in Bulletin 45 of the Storrs, Connecticut, agricultural experiment 
station. an | 
