64 



THE AMEEICAN ENTOMOLOGIST. 



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

 kindly furnished us with the drawing's, c, d, e, 

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

 hooks of both. That oi septemdecim 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 aif. 



By these figures, it will be seen that there 

 are sufficient diiferences to separate the two 

 forms as distinct; but we have since ascer- 

 tained — and the fact had been previously 

 remarked by Mr. P. R. Uhler, of Baltimore — 

 that while the hooks of the large kind (sep- 

 temdecim) are qviite constant in their appear- 

 ance, those of the smaller kind (cassinii) are 

 quite variable, and in some few specimens 

 are undistiuguishable from those of the large 

 kind. This circumstance, coupled with the fact 

 that the small kind regularly occurs with both 

 the 17 and 13-year bi-oods, would indicate it to 

 be but a dimorphous form of the larger, 

 or true periodical species; especially when 

 we consider that dimorjjhism and hetero- 

 morphism are not uncommon among the true 

 Bugs. "We also learn from Mr. Uhler, who has 

 given this order particular attention, that he is 

 not fully satisfied of the specific distinctness of 

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

 ject would involve the general problem of spe- 

 cific character, and as the opposite sexes of the 

 two foi-ms have never been seen in copulation, 

 we shall, for convenience sake, regard them as 

 distinct. 



The large species has been observed to make 

 its appearance from eight to ton days earlier 

 than the small species (cassinii), and there is 

 not a single specimen of the latter, among a 

 number of the 13-year brood (tredecim) that we 

 captured in May, though we took a few speci- 

 mens afterwards. 



The Season of their Appearance and Disap- 

 pearance 



dift'ers somewhat with the latitude, though not 

 so materially as one might suppose. According 

 to the records, they appeared the past season 

 earlier in the South than in the North ; but the 

 last half of May can be set down as the pei'iod 

 during which they emerge from the ground, in 

 any part of the country, while they generally 

 leave by the U\i of July. As is the case with a 

 great many other insects, the males make their 

 appearance several days before the females, and 

 also disappear sooner. Hence in the latter part 

 of the Cicada season, though the woods are still 

 full of females, the song of but very few males 

 will be heard. 

 That circumstances favorable or otherwise 



maj' accelerate or retard their development, was 

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

 8. Hull, of Alton, Ills. ; as by constructing the 

 undergi-ound 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. Thfs 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 

 Gnntersville, Ala., to the Country Gentleman 

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

 locusts." Other such cases will be noticed 

 hereafter. 



Their Natnral 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. rao 



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

 has himself witnessed four of their periodical 

 visits, at intervals of 17 years, has communi- 

 cated to lis the following veiy ingenious provis- 

 ion, which the pupa (Fig. 59 a) made the past 

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

 which the drainage was impei-fect. He says: 

 " We had a series of heavy rains here about the 

 time of their first appearance, and in such places 



