190 INSECTS INJURIOUS TO VEGETATION. 



more common or more generally met with throughout the 

 State. It may be called the dog-day harvest-fly, or Cicada 

 canicularis, from the circumstance of its invariably appearing 

 w^ith the beginning of dog-days. During many years in suc- 

 cession, with only one or two exceptions, I have heard this 

 insect, on the twenty-fifth of July, for the first time in the 

 season, drumming in the trees, on some part of the day be- 

 tween the hours of ten in the morning and two in the after- 

 noon. It is true that all do not muster on the same day; for 

 at first they are few in number, and scattered at great distances 

 from each other; new-comers, however, are added from day to 

 day, till, in a short time, almost every tree seems to have its 

 musician, and the rolling of their drums may be heard in every 

 direction. This circumstance, however, does not render it any 

 the less remarkable that the first of the band should keep their 

 appointed time with such extreme regularity. The dog-day 

 harvest-fly measures about one inch and sLx tenths from the 

 front to the tips of the wing-covers, which, when spread, ex- 

 pand about three inches. Its body is black on the upper side ; 

 the under side of the head, the breast, and the sides of the 

 belly are covered with a white substance resembling flour; 

 the top of the head and the thorax are ornamented with olive- 

 green lines and characters, one of which, in the shape of the 

 letter W, is very conspicuous ; the legs, and the front edge and 

 principal veins of the wing-covers and of the wings are also 

 green, and there is a dusky zigzag spot on the little cross-veins 

 near the tip of the wing-covers; and the valves beneath the 

 body of the males are wider than long. This species has 

 heretofore been mistaken for the Cicada pruinosa, or frosted 

 harvest-fly, described by Mr. Say, which is found in the Middle 

 States, measures two inches to the tips of the wing-covers, has 

 a white spot each side of the base of the abdomen, a second 

 on the middle of the sides, and a third near to the tip, and has 

 the valves of the males longer than wide.* I am not aware 



* The form and proportions of the abdominal valves have decided me to 

 separate the canicitlaris from Mr. Say's prumosa, although, with the exception 

 of their difference in size, they present no other constant characters -which will 

 invariably serve to distinguish them from each other. 



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