26 
The young are usually olive-green. The wingless female, with its 
small gray body from a quarter to two-fifths of an inch in length 
and its rather long legs, gives more the impression of a spider than 
that of a moth. The chrysalis is pale grayish-brown, with a dark 
green tinge on the wing sheaths, and measures al3out a third of an 
inch in length. 
This insect has not recently been abundant in Chicago, but its 
capacities for injury are well illustrated in a recent attack on elms 
at Big Rock, Kane county. Some ten years ago it was generally 
prevalent thruout the south-central part of the state, both in 
towns and in forests, to which it had apparently escaped from neg- 
lected orchards, although in some cases orchards were invaded in 
turn from adjacent forests. A most threatening attack was made 
on the magnificent old elms of Jacksonville, but a vigorous cam- 
paign, first of spraying and later of the application of adhesive 
bands, presently brought the outbreak under control.* 
A cheap and available band for the trunk of a tree is made by 
laying around the trunk first a strip of unglazed cotton batting 
two or three inches wide and over this a four- to six-inch strip of 
tarred paper tied around the middle with ordinary wrapping twine. 
Upon this paper belt should be spread a layer a quarter of an inch 
thick of cheap printers' ink with which a small amount of car wheel 
oil has been mixed, just enough to make it easy to spread. If the 
tarred belt becomes slightly hardened by exposure so as to permit 
an insect to cross, it may be made sticky again by brushing it with 
a little of the same kind of oil. The cotton batting beneath the 
paper is necessary to keep the young canker-worms or the female 
moths from crawling up behind the paper where the roughness of 
the bark would give them passagew^ay. These bands should be 
placed on the tree as early as the middle of February or the first 
'of March, the time varying according to the latitude, and they may 
be safely removed by the middle of June. The cost of the bands 
will approximate ten cents a tree. 
If the canker-worms have already ascended the tree, it is some- 
times necessary to spray the leaves with an arsenical poison, which 
may be either arsenate of lead or Paris green, the latter at the rate 
of one pound of the poison and one pound of lime to seventy-five 
gallons of water. If the arsenate of lead is used, three pounds of 
it dissolved in fifty gallons of water will kill even the full-grown 
caterpillars. 
♦The Canker-worm on Shade and Forest Trees. By S. A. Forbes. Twen- 
ty-second Report State Ent. 111., page 139. 
