ENTOMOLOGY. 



319 



existiiio-. It is advised tliat the egg- masses of the moths be eolleeted 

 b^' baud during the winter and destroyed. The natural parasites will 

 destroy many of the caterpillars that might liatch from eggs which are 

 overlooked. The ravages of the caterpillars may be checked by spray- 

 ing with Paris green. 



The sugar-maple borer has done considerable damage in the central 

 region of the State, producing holes as large as load pencils iii the bark 

 of the trunks and rapidly causing the foliage to yellow and the trees to 

 appear unhealthy. The beetles emerge in July and August, soon lay- 

 ing eggs that quickly liatch. The larvic burrow obliquely upward 

 through the bark in which they remain until spring, when they bur- 

 row into the wood, which they mine in all directions. The attacks of 

 the insects seem to be confined to the sugar maple {Acer saccharinum). 

 Indication of the borers is generally shown by the brownish sawdust- 

 like casting thrown out of the hole, by means of which the larvic can 

 be located and may be dug out with a sharp knife during the hibernat- 

 ing season. Seriously injured trees should be cut down and burned 

 before the larviie mature. 



The use of arsenites on tobacco, H. Garman [Kentucly Sta. Bid. 

 63, pp. 68-80, pis. 2). — The author has conducted a series of experiments 

 on the effect of spraying tobacco with different preparations of Paris 

 green. From 1 to 8 applications were given the different plats, begin- 

 ning July 3. The amount of injury done by the worms to the plants in 

 the different plats is tabulated. The quantity of liquid used and the 

 amount of Paris green which each plant received are given. 



The amount of arsenic acid found in a sample of tobacco from the 

 different sjirayings is shown in the following table, compiled from the 

 averages of 2 sei^arate determinations: 



Arseitious oxid in dnj tohacco. 



' These plants were (ait as soon as they were dry from the second spraying. 



The question whether or not any danger to the consumer would 

 accrue from the practice of using arsenites is still open to discussion, 

 but it is thought that the small amount found even in the samples 

 giving the largest content would not do any serious injury. 



Numerous experiments Avere conducted to ascertain the proportion of 

 Paris green necessary to be used. 



