. 492 
ANNUAL REPORT OF NEW YORK 
ONION-PLY. FLY DESCRIBED. PARASITES. OTHER DESTROTERS. 
side this is observed as being smaller and more slender in its form. 
It is represented in the annexed cut, 
Fig. 5, the cross lines showing its 
natural dimensions when its wings are 
extended. The two sexes are readily 
distinguished from each other by the 
e} r es, which in the males are close to¬ 
gether and so large as to occupy 
almost the whole surface of the head, 
*ig a. umuu-uj. whilst in the female they are widely 
separated from each other. These flies are of an ash gray color, 
with the head silvery, and a rusty black stripe between the eyes, 
forked at its hind end. And the species is particularly distin¬ 
guished by having a row of black spots along the middle of the 
abdomen or hind body, which sometimes run into each other, and 
then forming a continuous black stripe. This row of spots is quite 
distinct in the male, but in the female it is very faint or is often 
wholly imperceptible. This fly measures 0.22 to 0.25 in length, 
the females being usually rather larger than the males. 
On examining the diseased onions we find the operations of these 
worms vary considerably in different instances. Sometimes a round 
hole is bored, either in the side or the bottom of the onion, and only 
one worm is present. More commonly several worms of different 
sizes are found, and if the plant is young, with the root cylindrical, 
it is cut completely asunder, as represented, Fig. 1. If it is more 
advanced and the bulb partly formed, a large, irregular cavity 
will be found in its centre, as shown by Fig. 2, and the earth 
around the orifice is wet and slimy, forming a large, muddy mass, 
into which the maggots crawl to repose when not engaged in feed¬ 
ing. From being thus perforated and gnawed, the onion soon 
perishes and becomes soft and putrid, except its bottom part, 
which, continuing to be nourished by the fibrous rootlets, remains 
sound, and the larger worms thereupon crawl into this part to 
feed, whereby we sometimes meet with it presenting the appear¬ 
ance shown in Fig. 3, being thronged with worms, wedged 
together in a compact mass, as already described. 
Wo learn from Bouch6 (Garden Insects, page 131), that the 
Alysia manducator of Panzer is the parasitic destroyer ol different 
species of Antliomyia. This is a small black four-winged Ichneu¬ 
mon-fly, which in Europe is frequently to be seen upon and around 
