176 INSECTS INJURIOUS TO VEGETATION. 



circumstance of its invariably appearing with the beginning of 

 dog-days. During many years in succession, 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 between the hours of ten in the morning and 

 two in the afternoon. 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 six 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 

 thevving-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 

 lips 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*. 



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

 the canicularis from Mr. Say's prninosa, although, with the exception of their dif- 

 fer^ce in size, they present no other constant characters which will invariably 

 serve to distinguish themfroin each other. In my collection are four more native 

 species of Cicada ; namely, the auletes of Germar, our largest species, from North 

 Carolina ; a second species, apparently undescribed, about equal to this in magni- 

 tude, from Long- Island, New York ; the tibicen of LinnEeus, also from New York, 

 and quite common even within the city ; and the hieroghjphica of Say, which, 1 



