LETTER OF TRANSMITTAL. 
U. S. DEPARTMENT OF AGRICULTURE, 
BureEAv or ENTOMOLOGY, 
Washington, D. C., April 16, 1907. 
Sir: The subject of the periodical or 17-year Cicada has been 
treated in two publications of this Bureau, namely, Bulletin No. 8 
(old series), published in 1885, and Bulletin No. 14 (new series), 
published in 1898. Both of these publications are now out of print, 
and the accumulation of a large amount of new records of distribu- 
tion and the increase of information on the habits of this insect call 
for a new publication. Mr. C. L. Marlatt, who was the author of 
Bulletin No. 14, has thoroughly revised that publication, incorpo- 
rating all new records and information, and the manuscript is sub- 
mitted for publication as Bulletin No. 71 of this Bureau. 
In this publication the new numbering of the broods suggested by 
Mr. Marlatt in Bulletin No. 18 (new series), of this Bureau, is fol- 
lowed, so that now the designation of the broods indicates directly 
their relationship to each other in time and distribution. 
The writings on this species are voluminous, and the bibliography 
published in Bulletin No. 14 has been extended to include the 
important additions to the literature which have appeared since 1898. 
A good deal of the matter from Bulletin No. 14 has been used with- 
out change, but the brood records have been thoroughly revised and a 
distribution map has been made for each of the known broods. Some 
new photographs have ,been introduced to illustrate particular fea- 
tures of the life history of the Cicada. 
The periodical Cicada covers in its range nearly all of the United 
States from the Mississippi Valley eastward, and has a very consid- 
erable economic importance. The curious features of its regular 
periodic appearances and its long subterranean life give it perhaps 
the greatest popular interest which attaches to any insect whatever, 
and lead to many inquiries with every recurrence of an important 
brood. 
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