G. GENERAL NATURAL HISTORY AND ZOOLOGY. 3 2*7 



dieted that "in the year 1876, and at intervals of seventeen 

 years thereafter, they will in all probability appear from 

 Raleigh, jST.C, to near Petersburg, Virginia; in Rowan, Davie, 

 Cabarras, and Iredell counties in North Carolina ; in the 

 valley of Virginia, as far as the Blue Ridge on the east, the 

 Potomac River on the north, the Tennessee and North Caro- 

 lina lines on the south, and for several counties west ; in the 

 south part of St. Mary's County, Maryland, dividing the 

 county about midway east and west; in Illinois about Al- 

 ton ; and in Sullivan and Knox counties, Indiana." Speci- 

 mens since received from Lexington, Virginia, Avere proof of 

 the correctness of the prediction in regard to Virginia. While 

 this insect requires thirteen or seventeen years, according to 

 the race, for its underground development, the actual devel- 

 opment has never been watched from the egg to the mature 

 insect. In 1868 he had collected together in a particular 

 spot near St. Louis a large number of the hatching eggs of 

 a thirteen-year brood which will appear there again in 1881, 

 and he had been able to obtain and note the development of 

 the larvae every year since. They are now (1876) about two 

 tliirds grown. American JSfatiiralist^ October. 



HOW COCKROACHES AND EARWIGS FOLD THEIR WaNGS. 



Several years ago Dr. Saussure, of Geneva, published some 

 interestino; observations on the structure of the winQ-s of 

 cockroaches. He treated particularly of the folding of the 

 wings in those forms w^here the wing is very ample, and 

 some contrivance necessary to insure its complete protection 

 by the small wing-covers. The necessity of some peculiar 

 arrangrement in the winered crenera of earwiors, where the ex- 

 tended wins: is often ten times laro-er than the wing^-covers, 

 is even more evident, and to enable one to understand the 

 subject Mr. S. H. Scudder gives a resume of Saussure's paper, 

 with additions of his own. In the earwig {Forjicida) the 

 wings are folded much as in the cockroach. The mode in 

 which they are opened would be much more difficult to un- 

 derstand if it had not been observed by Charpentier, and 

 described nearly forty years ago. The contraction of the 

 extensor muscles attached to the hinder set of veins would 

 undoubtedly cause the fan to expand when once the double 

 folding, transverse and longitudinal, had been overcome ; but 



