10 



BULLETIN' 273, IT. S. DEPARTMENT OF AGRICULTURE. 



The first larva was caught May 9 and the last June 5, although 

 examinations of later date were made. These dates indicate the 

 range of the wind dispersion period for that section in 1913. The 

 distance borne by the wind was 1 mile or more. 



Another small experiment was conducted 200 feet from the above 

 screen by attaching to the northwest, west, and southwest sides of a 

 small stable 77 square feet of cotton cloth which was smeared with 

 tanglefoot. This experiment was not started at the beginning of 

 the season, but 9 larvas were blown into the tanglefooted cloth be- 

 tween May 20 and 31. The object in this experiment was to ascer- 

 tain the comparative efficiency of tanglefooted wire screen and a solid 

 tanglefooted surface as traps. 



CONTINUATION OF SCREEN EXPERIMENT AT SALISBURY BEACH, MASS., 



IN 1914. 



The same screen (PL III, fig. 1) as was erected in 1913 was cleaned 

 and retanglefooted for the dispersion season of 1914. The infesta- 

 tion in the woodlands to the westward, owing to the increase of 

 Calosoma sycoplianta L., Comjpsilura concinnata Meig., and the wilt 

 disease, was less intense during the latter year. The dispersion 

 period was much later and consequently much shorter than in 1913. 

 Examinations were begun about the time the hatching of eggs was 

 first noted in the field. The first caterpillar was caught May 19 and 

 the last May 31 in this location. 



The weather records were taken 1 mile south for this point at Plum 

 Island, Mass. (PL II), by Mr. C. E. Hood, and were compared with 

 those of the United States Weather Bureau at Boston, Mass., from 

 which they differed very little. 



Table III. — Dates and numbers of newly hatched caterpillars caught on screen, with tem- 

 perature, direction of wind, and velocity of wind, at Salisbury Beach, Mass., in 1914- 



Date and time removed. 



Number 

 of cater- 

 pillars 

 caught. 



Maxi- 

 mum 

 tempera- 

 ture. 



Mini- 

 mum 

 tempera 

 ture. 



Average between 8 a. m. and 

 5p. m. 



Prevailing wind 

 direction. 



Wind veloo- 



ity, in miles 



per hour. 



May 19, a. m 



May 20, a. m 



?vlay 21, a. m. and p. m 



May 22, a. m 



May 23, a. m. and p. m 

 May 24, a. m. and p. m 



May 25, a. m 



May 26, a. m 



May 27, a. m 



May 28, a. m 



May 29, a. m. and p. m 



May 30, a. m 



May 31, a. m. and p. m 



Total 



84 



W. and NW. 

 W. and NW . 

 NE.toSE... 

 E.andSE... 



W 



W 



sw 



SW.and W.. 



W.toS 



NW 



E.andSE ... 



SW 



W 



8 to 12 

 2 to 6 

 7 to 11 

 2 to 10 



10 to 23 



11 to 16 



12 to 21 

 7 to 20 

 4 to 12 



11 to 20 



9 to 17 

 7 to 9 

 7 to 14 



