160 TRANSACTIOi^S OP THE [1892 



our insect in the collection of Fabricius, and from Mm I 

 have received a positive identification of our species. 



The late Mr. Francis Walker also kindly sent to me 

 several specimens, from various parts of North America, 

 which display a wide range of variation in the markings 

 of the head and thorax. Individuals of this species are 

 occasionally found which show but a trace of the brown 

 W-shaped mark near the tip of the wing-covers. I have 

 also examined two specimens, otherwise normal, from 

 which this mark was entirely absent. 



The same thing likewise occurs with Tympanoterpes 

 gigas Oliv.; Cicada canicularis Harris ; C. dorsata Say ; 

 C. 7nontezu7na Dist.; C. biconica Walk., and most commonly 

 of all, with C. auletes G-erm., {ynarginata Say.) The 

 cause of this absence of the forked venal mark is not 

 adequately known. It seems to be absent only in very 

 few individuals of a species. Possibly, the less vigorous 

 and sensitive condition of some individuals at the time 

 of oxydation of the integuments hinders the complete 

 flow of the blood to this part of the venation and fails to 

 furnish the chemical elements upon v>^hich radiant energy 

 acts in developing color. 



2. C. margi7iata Say, Journ. Acad. Philada., v. lY., 1825, 

 p. 330, No. 2, Cicada auletes G-erm. Silb. Pev. Ent., 

 V. II., p. 65, No. 26. Cicada resli Hald., Salt Lake 

 Exped., p. 369, i3l. 9, fig. 17. Cicada so7iora Walk. 

 Brit. Mus. Cat. Hom., v. I., p. 105, No. 5. Cicada 

 reso7ia7is Walk, ib., v. I., p. 106, No. 6. FidAci7ia 

 liter ata Walk, ib, p. 91, No. 23. Fidicina figu7'ata 

 Walk. ib-/suppl. p. 19. 



This large species is distributed throughout the Pied- 

 mont region of the United States from New York to 

 Northern Florida. It is also found in the Gulf States, 

 and spreads on through Texas, Arkansas and Missouri 

 to Colorado and Utah. 



