THE DWARF PERIODICAL CICADA. 1 7 
Should the period of development of* the 13-year race be uninflu- 
enced by the colder and longer winters of their new location, the 
insects having survived, the adults should appear during the present 
summer. If, however, the greater cold, and especially the longer win- 
ters, be the cause of the longer period of the northern broods we may 
not expect the adults to emerge from these plantings of eggs for two, 
three, or perhaps four years. It is hoped that the persons who were 
intrusted with these experiments will keep a sharp lookout for adults 
during the present and the following three years. 
With the 17-year race (Brood XXII), which was transferred to vari- 
ous points in the South, careful watch should also be kept during the 
present summer and the following four summers for the emergence of 
representatives of this northern brood. 
It seems improbable that the term of development should be entirely 
changed in a single generation; but that the transfer in question may 
influence development to the extent of accelerating the emergence 
in one case and retarding it in the other for a year or more may be 
confidently expected. 1 
THE DWARF PERIODICAL CICADA. 
Ill connection with the discussion of the 13-year and 17-year races of 
the Cicada, it is interesting to note also that in both races the insect 
occurs in two distinct types, viz. a large form and a small form, 
the former comprising the bulk of the individuals of the brood and 
the latter more rare and ofteu unobserved. The existence of these 
two types was commented upon as early as 1830 by Dr. Hildreth, of 
Marietta. Ohio, 2 and was especially remarked in the great Cicada year 
18G8. The typical larger Cicada (tig. 1, A) measures on an average U 
inches from the head to the tip of the closed wings and expands over 3 
inches. The underside of the abdomen is of a dull orange brown color, 
and in the male four or five segments are of the same color on the 
back. The smaller form is rarely more than two-thirds the size of 
the larger, and usually lacks altogether the light abdominal markings, 
although they are sometimes represented on the edge of the segments 
beneath. 
The small form (fig. 1, B) was described in 1851 as a distinct species, 
Cicada cassinii, by Dr. J. 0. Fisher. 3 The contention that it represents 
a distinct species was urged particularly on the ground that there exists 
a variation in the genitalia, but this variation has since been shown by 
Professor Riley not to be constant, and specimens are to be found in 
both sizes which present the same structure in these parts. In view of 
this tact, and that they always occur together in the same brood, the 
specific importance of the smaller Cicada is not now admitted, and it 
l The records for L896 are given in Appendix A. 
3 Silliman's Journal, XVIII, p. IT. 
Troc. Plula. Acad. Nat. So., Vol, \ .. i>. 872, 
