INJURIOUS AND BENEFICIAL INSECTS. 541 
that it also appeared in 1838, 1855 and 1872. In Sandwich it 
appeared in 1787, 1804 and 1821. In Fall River it appeared in 
1834; in Hadley in 1818; in Bristol county in 1784, so that as 
remarked by Harris and others it appears at different years in 
places not far from each other. So that while in Plymouth and 
Sandwich we may look for its reappearance in 1889, in Fall River 
it will come in 1885, or four years earlier. 
There are three species of cicada in this state, and in order that 
they may not be confounded in studying the times of appearance 
of the different broods of the seventeen-year spe- 
cies I add a short description of each form, so that 
they may be readily recognized in the winged and 
immature states. 
The two largest species are the seventeen-year 
locust (Cicada septendecim) and the dog-day cicada 
(C. pruinosa). Fig. 142, copied from Riley’s re- 
port gives a good idea of this species: a represents 
the pupa; b the same after the adult has escaped 
through the rent in the back; c the winged fly; d 
the holes in which the eggs e are inserted. Fig. 
143 represents the larva as soon as hatched. The 
adult may be known by its rather narrow head, -arva of Seven- 
the black body and bright red veins of the wings, ten-year Cicada. 
The wings expand from two and a half to three and a quarter 
> inches. 
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The pupa is long and narrow, and compared with that of C. pruinosa the head 
is longer and narrower, the antennæ considerably longer, the separate joints being 
nearer the end; the next spine, the basal one of the series of five, is three times as 
large as the next one, while in C. pruinosa it is of the same size, or if anything smaller. 
Tha + zas x a à: VE E: R : 1 A SN A af th hank 
(tibia), while in the other species it only projects half its length. The terminal seg- 
ment of the body is rather larger than in C. pruinosa. ody is shining gum-color 
darker than the rest of the body. Length one inch 
being rather smaller than that of C. pruinosa and much larger that of 
The dog-day harvest-fly may at once be known by its large 
head, as wide as the body, and by the green markings on the 
head and thorax, especially the W-shaped mark on the latter. It 
expands three inches, and is a larger and more bulky insect than 
