ONION FLY. 
69 
and putting a tarred band round the base of the trunks of the forest 
trees, so that they could not make their way back again, would be a 
thorough cure. For young trees in nurseries Mr. MTntosli suggests 
that some sticky fluid or mixture [? Davidson’s composition, Ed.] 
would be of great service. 
The caterpillars are somewhat downy, yellow or tawny, marked 
with black lines, or long black spots interrupted at the joints, so as to 
give the appearance of upright orange streaks at intervals, and have 
black heads. They come to their full size, which is an inch and 
three-quarters long (see figure), from August to September, and then 
come down from the tree and change to brown chrysalids either on 
the ground or amongst roots or rubbish just at the surface. The 
moths from these come out in the following June, and are large 
and prettily marked. The head and fore part of the body between the 
wings is yellow, and the abdomen mostly pale yellow. It has the 
fore wings of a silvery grey, with various markings of black and rusty 
colour mostly placed in single or double lines, and with a yellow or 
ochrey patch at the tip, whence the name of the moth. The lower 
wings are whitish. The eggs are laid early in June or July. 
I have seen the caterpillars do great damage in the neighbourhood 
of Isleworth, and the attack appears to be just one of those which 
may be very often got rid of by a little trouble, but which will be 
likely to do a great deal of mischief if not attended to. Shaking down 
the caterpillars and killing them when fallen, together with such 
measures as will keep them from crawling up the tree again, will get 
rid of a great many; and soft-soap washes (for various kinds of 
which see Index) would be of great use in clearing them off low trees 
or in nurseries. 
ONIONS. 
Onion Fly. Anthomyia ceparum, Curtis. 
During the two seasons previous to 1884 I experimented on the 
effect of covering Onion bulbs up to the neck (or rather higher) with 
earth, so that the Fly could not get at the bulb to lay its eggs ; and, 
on the small scale on which I was able to work the plan, I found it 
answer so well that during last season (1884) I again tried the plan of 
burying the Onions, but on a more definite method, and met with great 
success. 
The principle of the arrangement was, that as the flies usually laid 
their eggs on the bulb itself (especially the lower part, and beneath 
