80 



of April, and, when placed in the cage with opening apple buds, nibbled 

 a little, but almost immediately changed to pupae within a cluster of 

 webbed leaves. Pupa smooth, dark brown, without any especially dis- 

 tinguishing characters. Three imagines appeared April 24. 'They were 

 of a species which had been long before determined for me as a Palthzs 

 angulalis. 



With the idea that possibly the immature stages of this insect had 

 not previously been observed, I submit the above descriptions. 



INSECTICIDES. 



White arsenic in ammoniacal solution — 1 ounce arsenic to 1 quart aqua 

 ammonia — one tablespoonful of this to a gallon of water proved a 

 failure in the case of most insects, while it still scorched the leaves 

 somewhat. 



A soda solution made on a smaller scale had much the same effect on 

 the foliage of peach and plum trees, and was not, so far as could be 

 observed, efficient in protecting the fruit from curculio. 



White arsenic in boiling water, the latter being only a partial sol- 

 vent, in the proportion of an ounce of arsenic to 20 gallons of water, 

 was sprayed upon young peach and plum trees without injury to the 

 foliage. The frequent rains of the late spjring and early summer ren- 

 dered many of the applications futile in the case of the curculio and cod- 

 ling moth. Paris green in liquid, 1 pound to 100 gallons of water, has 

 been found the safest and most reliable insecticide for use against 

 the canker-worm and codling moth. Its effects on insect life seem to 

 be due not alone to the percentage of arsenic, but to the general com- 

 bination, while on vegetation it produces less injury than London pur- 

 ple or any of the solutions of pure arsenic. 



In my somewhat limited experience the petroleum emulsions can not 

 be excelled as a remedy for all species of scale insects, and when ap- 

 plied according to instructions, do no appreciable injury to trees and 

 shrubs. 



X. 0. Dust. — Late in May I received from the Department a package 

 of this new patented insecticide, with instructions to test its value on 

 various iujurious insects. It is to be applied full strength and claims 

 to kill by contact and at the same time to be innoxious to man and the 

 higher animals and to vegetable life. 



June i. — Applied the powder about 9 o'clock in the morning to Bory- 

 phora larvae on potato, to late specimens of the rose-slug (Selandria 

 rosm), to Aphis persicw on young peach and plum trees, and to Aphis 

 sp.1 on chrysanthemums; also to young cabbages and radishes, on 

 which flea beetles {PhyUotreta vittata and zimmermanni) were abundant 

 and destructive. Three hours later visited these plants and noted fol- 

 lowing results : Eose-slugs considerably affected, showing symptoms of 

 sickness and paralysis and dropping from the leave* when jarred. 

 Boryphora larvae not seriously affected, only the smaller ones had 

 dropped, while some of those nearly grown continued feeding, appar- 



