86 



September, and were very noticeable towards night, feeding on 

 the honeydew on pear leaves, secreted by the Pear Psylla [Psylla 

 pyri], which was very abundant. 



It appears to be always the later generation which does the damage 

 and the caterpillars of which march in armies. The army worm 

 generally feeds in low meadows, near swamps, where the grass is rank, 

 and its appearance in large armies seems to be due to the exhaustion 

 of its food-supply. Though usually feeding only on grasses and grains, 

 under the pressure of hunger it may attack many cultivated plants. 

 When abundant in its swampy haunts, it may be controlled by spray- 

 ing w^ith Paris green, 3 pounds to 75 U.S. gallons (62 Impl.) of water, 

 or arsenate of lead, at least 5 pounds to 50 U.S. gallons (41| Impl.) 

 of water. This treatment destroys the grass or crops the caterpillars 

 may be feeding upon, but checks the spread of the invading army. 

 Sometimes it is possible to place a thick strip of Tarvia (road oil) 

 across the line of march, which should be continually renewed. A 

 furrow across their track or a band of powdered agricultural 

 lime an inch or more deep are quite effective barriers. Excellent 

 results attended the use of a bran mash bait prepared by taking 1 lb. 

 Paris green, 25 lb. bran or middlings, 2 quarts of cheap molasses, 

 and water to make a thick mash when thoroughly stirred. The cater- 

 pillars fed freely on it when it was placed in strips across the line of 

 march or spread broadcast, but birds feeding upon it or upon the 

 poisoned caterpillars will also be poisoned. 



Masher (F. H.) & Webber (R. T.). The Relation of Variation in the 

 Number of Larval Stages to Sex Development in the Gipsy Moth. — 

 Jl. Econ. Entom., Concord, vii, no. 5, October 1914, pp. 368-273. 



Experiments on the food-plants of Lymantria dispar, L., have in- 

 cidentally shown that there is a more or less constant difference in 

 the stages in which the larvae spin up previous to pupating, and that 

 those larvae which pupate in the 5th stage produce males, while those 

 having a 6th stage .develop females. A repetition of these feeding 

 experiments in 1913 corroborated this, and of 56 fifth stage larvae, six 

 were parasitised, four diseased, and the remaining 46 produced male 

 pupae ; of 26 sixth stage larvae, three were parasitised, and the re- 

 maining 23 developed females. The development of a 7th stage was 

 not observed. It is stated that L. dispar is evidently changing its 

 habits in the United States ; 16 or 17 years ago, elm, barberry and 

 many other trees and shrubs which are to-day rarely infested by the 

 gipsy moth, were reported as common food-plants. L. dispar is itself 

 less hardy and more susceptible to disease and there is a perceptible 

 decrease in the average number of eggs laid except in newly infested 

 localities. 



Felt (E. P.). Notes on Forest Insects. — Jl. Econ. Entom., Concord, 

 vii, no. 5, October 1914, pp. 373-375. 



Malacosoma disstria, Hb., was exceptionally abundant in 1912 

 and 1913, and in 1914 it stripped oaks on Long Island and sugar maples 

 in the Hudson and St. Lawrence valleys. Extensive areas of poplar 

 were also defoliated, a marked preference being shown for the tops of 



