64 



THE AMEEICAN ENTOMOLOGIST. 



H. Hagen, of Cambridge, Mass., who very 

 kindly furnislied us "witli the drawings, c, d, c, 

 and /, in Fig. 58, which show the male genital 

 hooks of both. That oi septemdechn is repre- 

 sented on the outside at c. on the inside at d; 

 and that of cassinii on the outside at e, and on 

 the inside at/. 



By these figures, it will be seen that there 

 are sutficient diflerences to separate the two 

 forms as distinct; but we have since ascer- 

 tained—and the fact had been previously 

 remarked by Mr. P. U. Uliler, of Baltimore — 

 that Avhilc the hooks of the large kind (sep- 

 femdechn) are quite constant in their appear- 

 ance, those of the smaller kind {cassinii) are 

 quite variable, and in some few specimens 

 are undistinguisliable Irom those of the large 

 kind. This circiunstancc, coupled with the fact 

 that the small kind regularly occurs with both 

 the 17 and 13-year broods, would indicate it to 

 be but a dimorphous form of the larger, 

 or true periodical species; especially when 

 we consider that dimorphism and hetero- 

 morphism are not uncommon among the true 

 Bugs. We also learn from Mr. Uhler, M'ho has 

 given this order particular attention, that he is 

 not fully satisfied of the specific distinctness of 

 C. cassinii; but as the consideration of tliis sub- 

 irr-t would involve the general problem of spe- 

 iharacter, and as the opposite sexes of the 

 ^n-ms have ucver been seen in copulation, 

 all, for convenience sake, regard them as 

 ■■■t. 



^ large species has been obsciwed to make 

 .pearance from eight to ten days earlier 

 he small species {cassinii), and there is 

 single specimen of the latter, among a 

 •;r of the 13-year brood (tredecim) that wc 



I'-d in May, though wc took a few spccl- 

 fterwards. 

 ■ason of tlioir Appearance antl Disap- 

 pearance 

 somewhat with the latitude, though not 

 ■ rially as one might suppose. According 

 records, they appeared the past season 

 in the South than in the North; but the 

 if of May can be set down as the period 

 i which they emerge from the ground, in 

 at of the country, while they generally 

 oy the 4th of July. As is the case with a 

 many other insects, the males make their 

 ■arauce several days before the females, and 

 disappear sooner. Hence in the latter part 

 .'.a Cicada season, though the woods are still 

 .ill of females, the song of but very few males 

 will be heard. 

 That circumstances favorable or otherwise 



may accelerate or retard their development, was 

 accidentally proven, the past season, by Dr. E. 

 S. Hull, of Alton, Ills.; as by consti-ucting the 

 underground flues, spoked of on page 9 of our 

 first number, for the purpose of forcing vegeta- 

 bles, he also caused the Cicadas to issue as early 

 as the 20th of March, and at consecutive periods 

 afterwards, till May, though strange to say these 

 premature individuals did not sing. They fre- 

 quently appear in small numbers, and more 

 rarely in large numbers, the year before or the 

 year after their proper period. This is more es- 

 pecially the case with the 13-year brood. Thus 

 in Madison county in Illinois, and in Daviess 

 and Luray counties in Missouri, there were in 

 1854 a few precursors to the true 1855 brood. 

 They were also observed in Madison county, Il- 

 linois, in 1867; while "L. W.," writing from 

 Guntersville, Ala., to the Country Gentleman 

 of June 25, 1868, says, "some call them 14-year 

 locusts."' Other such cases will be noticed 

 hereafter. 



Their Natural History and Transformations 



have been sufficiently described in the standard 

 works of both Harris and Fitch, and we shall 

 simply mention a few facts not recorded by them. 



[Fig. 59.] 



Mr. S. S. Rathvon, of Lancaster, Pa., who 

 has himself witnessed four of their periodical 

 visits, at intervals of 17 years, has communi- 

 cated to us the following very ingenious provis- 

 ion, which the pupa (Fig. 69 a) made the past 

 season, in localities that were low or flat, and in 

 which the drainage was imperfect. He says: 

 " We had a series of heavy rains here about the 

 time of their first appearance, and in such places 



