THE OXION-FLY. 
617 
maggots, and rendered unfit to be eaten. These maggots 
are finally transformed to small, ash-colored flies, with a 
silvery-gray face, copper-colored eyes, and a brown spot on 
the forehead of the females ; they have some faint brownish 
lines on the thorax, and a longitudinal black line on the 
hind body, crossed by narrower black lines on the edges 
of the rings. They vary in size, but usually measure rather 
more than one fifth of an inch in length. They finish their 
transformations, and appear above ground, towards the end 
of June. The radish-fly is called Anthomyia Raphani, in 
my Catalogue, from the botanical name of the radish, on 
the root of which its larvas feed. It closely resembles the 
root-fly ( Anthomyia radicum ) of Europe. 
Onions, soon after they come up in the spring, and until 
they are grown to a considerable size, are often observed to 
turn yellow and die. Many years ago I remember to have 
seen them extensively affected in this way, so that there was 
a failure of three fourths of the plants in a largo bed. The 
cause of their death was not suspected at the time, and no 
examination was made for the discovery of insects in them. 
Since then, I have been favored by Mr. Westwood with 
copies of two articles* by him, on the onion-fly ( Anthomyia 
Ceparu.vi'), (Fig. 272, pupa and imago,) 
which, in the maggot state, lives in the roots 
of onion-plants in Europe, and causes them to 
wither and perish exactly in the same way as 
young onions do here. Hence there is good 
reason to believe that the failure of our onion crop is caused 
by the ravages of maggots similar to those of the European 
onion-fly. The latter lays its eggs on the leaves of the 
onion, close to the earth, so that the maggots, when hatched, 
readily make their way to the heart of the onion. The 
maggots come to their growth in about two weeks, turn to 
DO O 
* See the Magazine of Natural History, Vol. VII. p. 425, and the Gardener's 
Magazine. Vol. XIII. p. 241. The same insect is also described and figured in 
Hollar's Treatise, p. 157. 
Fig. 272. 
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