540 INJURIOUS AND BENEFICIAL INSECTS. 
Mr. Riley, in an interesting account of this cicada in his “First 
Annual Report on Noxious, Beneficial, and other Insects of Mis- 
souri” for 1869, has shown that in the southern states thirteen- 
year broods of this insect are found. He remarks: ‘It was my 
good fortune to observe that besides the seventeen-year broods, 
the appearance of one of which was recorded as long ago as 1633, 
there are also thirteen-year broods, and that, though both some- 
times occur in the same states, yet in general terms, the seventeen- 
year broods may be said to belong to the northern and the thir- 
teen-year broods to the southern states, the dividing line being 
about latitude 
thirty-eight de- 
grees, though in 
some places the 
seventeen-y ear 
brood extends 
below this line, 
while in Illinois 
the thirteen- 
year brood runs 
up considerably 
ceedingly grati- 
fying to find, 
The Seventeen-year Cicada and Pupa. 
discovery had been made years before by Dr. Smith, though it 
had never been given to the world.” 
‘Mr. Riley predicts that in southern New England a brood will 
appear in 1877 and 1885. Probably the Plymouth brood which — 
appeared in 1872, will not appear again for seventeen years: 
namely, in 1889, the two broods noticed by Riley appearing west 
of this town. As regards its appearance in Plymouth, in this 
state, Harris states that it appeared there in 1633. The next 
date given is 1804, “ but, if the exact period of seventeen years 
had been observed, they should have returned in 1803.” 
Mr. B. M. Watson informs me from his personal observation, 
