February, '17] COLLINS: WIND AND GIPSY MOTH 171 



later discovered that the ahnond mite (Bryobia pratensis) was carried 

 extensively by the wind, having taken it on sticky fly paper 650 feet 

 from an infested orchard and on top of a schoolhouse 50 feet high. 

 Quayle^ has given us evidence that the young black scale {Saisettia 

 oleae) is dispersed by the wind as it was taken in tanglefoot 450 feet 

 from the nearest infested trees. This species was distributed over an 

 entire four-acre block of trees, chiefly by the wind in a single season. 

 The young of the red scale (Chrysomphalus aurantii) was also taken at 

 distances ranging from 30 to 150 feet. Titus^ has observed that young 

 thrips are carried by the wind at a height of 20 feet. 



Observations on time of hatching of gipsy moth eggs in comparison 

 with development of foliage in 1916 showed that Forsyihia vulgaris, a 

 common shrub on lawns in eastern Massachusetts is approximately in 

 full blossom just previous to hatching of the eggs. The garden cherry 

 (Prunus avium L.) and pear {Pyrus communis L.) also blossom just 

 previous to first hatching. Shad bush {Amelanchier canadensis) 

 blossoms about this time. The late varieties of apple first begin put- 

 ting out their leaves simultaneously with the first hatching. The 

 buds of some of the hardwoods in the woodlands, such as the hickories 

 and oaks begin putting out their leaves somewhat later than those of 

 the apple and simultaneously with general hatching of the gipsy moth. 

 Windspread of the newly hatched larvae closely follows hatching and 

 extends approximately over the same period, namely, from ten days 

 to three weeks depending upon the season. During a long cold spring, 

 development of the foliage and larvae is much retarded; hence wind 

 dispersion spreads over a longer period. 



In order to determine the direction from which larvae came when 

 found upon a screen at a stated time, it was necessary to keep detailed 

 records of the winds and temperatures during the dispersion period. The 

 activity of the young larvae is directly influenced by the temperature 

 and hourly readings were taken daily during the period of windspread. 

 A small weather vane was attached to one of the posts of the screen 

 under observation and hourly or half-hourly readings recorded. By 

 noting the time that each larva was found on the screen and figuring 

 back to the previous examination, it was possible to give the approxi- 

 mate direction and source from which they came. A small hand ane- 

 mometer was also used to record the velocity of the wind, an observa- 

 tion with which was taken hourly or every two hours. Use was also 

 made of the same weather data collected by the U. S. Weather Bureau 

 at Boston, Mass., Providence, R. I., Concord, N. H., and Portland, Me. 



^ Quayle, H. J. Dispersion of Scale Insects by the Wind. Journ. Econ. Ent., 

 vol. IX, No. 5, p. 486, 1916. 



2 Titus, E. G. Journ. Econ. Ent., vol. IX, No. 5, p. 492, 1916. 



