228 NATURAL SCIENCE [October 



the sudden appearance of a brood was believed to be the cause of a 

 " kinde of pestilent feaver." Eecords of the insect, during nearly 

 two centuries, over the eastern and central States, have shown that 

 there are two races, a northern with a seventeen-year, and a southern 

 with a thirteen-year life-cycle. A number of broods of each race 

 have been registered, and their distribution being known, the future 

 occurrences of the insect can be accurately forecast for the various 

 districts. Careful observations of the larval and nymph stages have 

 been made, and the changes undergone by the insect during its long 

 underground life have been traced. When development is com- 

 plete the nymphs of a brood leave the ground almost simultaneously, 

 and an alarming swarm of cicads is the result. The perfect insects 

 live but a few weeks, and are believed to take no food. The female 

 makes cuttings in tree-twigs wherein she deposits her eggs ; the 

 newly hatched larvae fall to the ground and burrow immediately. 

 The injury caused by the cicads is almost confined to their egg-laying 

 incisions ; though the larvae and nymphs suck sap from the roots of 

 plants, their slow rate of growth and feeding prevents them from 

 doing much damage. The life-cycle of this cicad is longer than that 

 of any known insect, but Mr Marlatt makes the probable suggestion 

 that other larger species of the family might be found to have even 

 longer larval stages, could the course of their generations be 

 accurately followed. 



The Larva of Pelophila 



In part 2 of the Transactions of the Entomological Society for the 

 present year (pp. 133-140), Messrs W. F. Johnson and G. H. 

 Carpenter make a contribution to the neglected subject of the life- 

 history of the Coleoptera, by describing with figures the grub of the 

 ground-beetle Pelophila borcalis, which they have discovered in Ire- 

 land. The larva agrees with those of the beetle's nearest relations 

 — Nebria and Lcistas — in possessing a pair of long, mobile cerci at 

 the hinder end of the abdomen, apparently a primitive character. 

 The head of the Pelophila grub, however, is broad and quadrate, and 

 the legs short, contrasting with the rounded head with constricted neck 

 and long legs of Nebria and Lcistus, and in these respects recalling 

 the structure of more generalised carabid larvae. 



Flat-Fish of South Africa 



Mi; J. D. F. Gilchrist, who was recently appointed Marine Biologist 

 to the Government of Cape Colony, is publishing in separate papers 

 descriptions by various specialists of the material which he collects. 

 These are entitled, " Marine Investigations in South Africa. Depart- 

 ment of Agriculture, Cape of Good Hope." We have received a 

 copy of a short paper on the Flat Fishes by Mr G. A. Boulenger. 



