THYSANOPTERA AND ORTHOPTERA. 219 



become as dry as it would at room temperature in ordinary atmosphere. 

 It was then found that it weighed 127 mg. 



From the data thus secured I compute that the grasshoppers in a 

 field of 27 acres may, in a grasshopper year, devour one ton of cured 

 hay per week. I am unable to state whether the eating of parts of a 

 timothy plant stimulates the rest to grow more rapidly. If it does 

 not, the farmer may compute, from the prevailing price of hay. how 

 much he can afford to spend in preventing the appearance of unusual 

 hordes of grasshoppers. 



DIURXAL ACTIVITY OF ACRIDIIDAE. 



While collections of this family were being made it became a matter 

 of some interest to know whether grasshoppers were more active at one 

 time of day than at another. Casual observations indicated that there 

 was a difference, but these observations were not trusted. Actual 

 counts were made under several different circumstances. The first 

 counts were made in a small cleared spot in the woods on Sand Point. 

 The area was elliptical, measuring perhaps four by eight rods. Small 

 bushes and herbs covered the ground, and several stumps, logs, and 

 brush heaps were present. The number of gras.shoppers in such a 

 place was limited. They were discovered by beating the weeds and 

 bushes carefully for five minutes. The operation was repeated in a 

 similar manner in the same clearing at intervals during most of the 

 forenoon. Unfortunately the counts could not be continued during 

 the day. The results are given in Table I. 



TABLE I. — Showing the number of Acridiidae that were flushed in a clearing in 

 five minutes, at different times. 



Time of making count. Number of grasshoppers flushed. 



Adult. Immature. 



6:30 a. m. . . 3 



7:40 a. m 4 • 9 



8:30a. m 4 9 



9:30 a. m 3 13 



10:30 a. m 2 9 



A second series of counts was made on one of the sparsely grass- 

 covered dunes along the north beach of Sand Point. The sand sloped 

 strongly toward the north. At each count an area was included which 



