18 
be reached in one way or another without much difficulty. The egg 
mass is compact, and, being attached to the somewhat flimsy cocoon 
and not to the bark, it is easily removed either by hand or by scraping 
it off. The egg masses which have been scraped off must not be 
allowed to remain at the surface of the ground, but should be collected 
and burned. A scraper for the removal of egg masses which occur too 
high to be reached by hand has been devised by Mr. Southwick, of 
Central Park, New York City, and consists of a very small hoe blade 
at the end of along pole. Perfectly unskilled Jabor can be utilized in 
this operation, but the workman should be impressed with the neces- 
sity of absolute thoroughness; not an egg mass should be overlooked. 

Fic. 7.—Silver maple leaves eaten by larve of white-marked tussock moth in successive stages of 
growth from a (newly hatched larvz) to f (full-grown larvze)—reduced (original). 
In the work against the gypsy moth in Massachusetts it has been 
found that the egg masses can not be removed to the best advantage 
by means of scrapers. The eggs are attached, not to the cocoons, but 
to the bark of the trees, and certain eggs may be left in the attempt 
to remove the mass. An extensive series of experiments has therefore 
been carried on with a view to securing a liquid which will penetrate 
and destroy the egg masses. 
A satisfactory liquid for this purpose has been found in creosote oil, 
to which turpentine is added to keep it liquid in cold weather, with tar 
to blacken it so that treated egg masses can be recognized at a glance. 
