ROSE GALL-FLIES. 
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them contains a single grub, and this in due time turns to 
a gall-fly, which may be called Cynips bicolor , the two-col- 
ored Cynips. Its head and thorax are black, and rough 
with numerous little pits ; its hind body is polished, and, 
with the legs, of a brownish-red color. It is a large insect 
compared with the size of its gall, measuring nearly one 
fifth of an inch in length, while the diameter of its gall, not 
including the prickles, rarely exceeds three tenths of an 
inch. 
Cynips dichlocerns, or the gall-fly with two-colored antennae, 
(Plate VIII. Fig. G, Fig. 7 magnified,) is of a brownish- 
red or cinnamon color, with four little longitudinal grooves 
on the top of the thorax, the lower part of the antennae red, 
and the remainder black. It varies in being darker some- 
times, and measures from one eighth to three sixteenths of 
an inch in length. Great numbers of these gall-flies are 
bred in the irregular woody galls, or long excrescences, of 
the stems of rose-hushes (Plate VIII. Fig 8). 
The small roots of rose-bushes, and of other plants of the 
same family, sometimes produce rounded, warty, and woody 
knobs, inhabited by numerous gall-insects, which, in coming 
out, pierce them with small holes on all sides. The winged 
insects closely resemble the dark varieties of the preceding 
species, in color, and in the little furrows on the thorax ; 
hut their legs are rather paler, and they do not measure 
more than one tenth of an inch in length. This species has 
been named Cynips semipiceus. 
Monstrous swellings of buds, and various other kinds of 
excrescences, may often lie seen on plants ; but my speci- 
mens of the insects producing them are not in a condition 
to be described. The foregoing account, however, will serve 
to illustrate the habits of some of our most common gall- 
flies, and explain the origin, forms, and structure of their 
singular productions. Such excrescences, as soon as they 
are observed on plants of any value, should immediately be 
cut off, and put into the fire. 
