FURTHER NOTES ON THE CHROMOSOMES OF THE 



CERCOPIM:. 



ALICE M. BORING AND RAYMOND H. FOOLER. 



The chromosomes in the spermatogenesis of five species of this 

 family of Hemiptera have already been studied by Stevens 1 

 and Boring. 2 Three more species have now been studied in 

 comparison with those previously studied. They are Philaenus 

 lineatus, Aphrophora paralJela and Clastoptera proteus. Each 

 of these three species belongs to a genus in which one or more 

 species has already been studied, so this gives a chance to compare 

 the spermatogenesis in closely related species. This has been 

 done very carefully by McClung 3 for some families of Orthoptera. 

 The entire family Acrididae has the same spermatogonial chro- 

 mosome number, 23, and the Locustidae has 33, but within each 

 family there are generic and specific cytological differences. 

 The family Cercopidae of the Hemiptera does not show as closely 

 graded a series of cytological differences as the orthopteran families 

 studied by McClung. The facts as found are here recorded. 



The material was collected at Woods Hole 4 and in Orono; 

 Philanus lineatus from grasses, Aphrophora parallela from Scotch 

 pines, and Clastoptera proteus from alders. Dr. Herbert Osborn 

 has very kindly identified the species of the material. Flem- 

 ming's and Gilson's solutions were used for fixation, and iron 

 hasmatoxylin for staining. 



Philcenus lineatus has 29 chromosomes as spermatogonial 

 number (Fig. i), two of which are larger than the others. The 

 odd chromosome is round or oval in the early (Fig. 2) as well as 



1 N. M. Stevens, '06, "Studies in Spermatogenesis," Pt. II., Carnegie Institute, 

 Washington. 



2 A. M. Boring, '07, "A Study of the Spermatogenesis in the Membracidae," etc., 

 Jour. Exp. Zool., 4, p. 469. '13, "The Chromosomes of the Cercopidae," BIOL. 

 BULL., 24, p. 133. 



3 C. E. McClung, '08, "Cytology and Taxonomy," Kans. Univ. Bull. 4. 



4 We wish to thank the Director of the Marine Biological Laboratory for the 

 privileges of the laboratory during the summers of 1913 and 1915, at which time this 



material was collected. 



312 



