4 S 6 the study of insects. 
tinct. The two following are well-known members of the 
Trypetinae. 
The Apple-maggot, Trypeta pomonella (Try-pe'ta pom-o- 
nel'la.)— This maggot eats into the pulp of apples, boring 
tunnels in all directions through the fruit; it attacks espe¬ 
cially the early maturing varieties. When full-grown it goes 
into the ground to transform. The adult is a black and 
white fly, with banded wings (Fig. 592). 
The Round Goldenrod Gall.—One of the most familiar 
of abnormal growths on plants is a ball-like enlargement of 
the stem of goldenrod (Fig. 593). 
L / This is caused by a maggot, which 
US lives within it, and which develops 
M into a pretty fly with banded wings. 
W This is Trypeta solidaginis (T. Sol-i- 
f dag'i-nis). There is another gall on 
Fig. 595-The Round Golden- the stem of goldenrod which is liable 
rod Gail. be mistaken for this one, but which 
can be easily distinguished from it. It is more elongate, 
and is hollow. It is made by the larva of a Tineid moth, 
Gelechia gallcesolidaginis (Gc-le'chi-a gal-lai-sol-i-dag'i-nis), it 
may be called the Elliptical Goldenrod Gall. 
The Stem-eyed Fly, Sphyracephala brevicornis (Sphyr-a- 
ceph'a-la brev-i-cor'nis) is a very singular fly, which is found 
on the leaves of skunk-cabbage. On each side of the head 
there is horn-like process extending outward, upon the end 
of which the eye is situated. This species is the only Amer¬ 
ican representative of its subfamily, the Diopsina: (Di-op- 
si'nae), yet described. 
The Cheese-maggot, Piophila casei (Pi oph'i-la ca'se-i) is 
the larva of a small black fly, less than half the size of the 
House-fly. It belongs to the small subfamily Piophilince 
(Pi-oph-i-li'nre), in which vein II of the wings is quite closely 
united with vein III. This fly lays its eggs on cheese, ham, 
and bacon ; the larvae live in these substances and are often 
serious pests. They are commonly known as “ skippers ” on 
