Vol.XXVni. April, 1915. No. 4. 



BIOLOGICAL BULLETIN 



LINKAGE OF CHROMOSOMES CORRELATED W 

 REDUCTION IN NUMBERS AMONG THE SPECIE^ 

 OF A GENUS, ALSO WITHIN A SPECIES OF 

 THE LOCUSTID^. 



CARRIE I. WOOLSEY. 



In the following paper it is my purpose to give the result of my 

 study of the chromosome numbers within three species of one 

 genus of the Jamaican LocustidcB. 



The material used was collected in Jamaica during the summer 

 of 1912 by Professor W. R. B. Robertson, of Kansas University. 

 The testes of all but one individual, No. 416, were removed while 

 in the field and fixed in either Bouin's or Flemming's fluid. The 

 slides were made in the fall of 191 2. The clearest and best divi- 

 sion figures as well as those in which the chromosomes were most 

 crowded together and unsatisfactory were made from Flemming- 

 fixed specimens. The sections were cut at about twelve micra 

 and iron-hematoxylin proved most satisfactory for staining. 

 All drawings have been made at the level of the base of the mic- 

 roscope with the aid of a camera lucida. A 2 mm. Spencer oil 

 immersion lens and No. 18 Zeiss compensating ocular were used. 

 All the figures were magnified to 3,900 diameters and have been 

 reduced 1/5, giving a final magnification of 3,120 diameters. 



The specimens studied were identified and classified by Mr. 

 A. N. Caudell of the United States National Museum, Washing- 

 ton, D. C, as follows: 



588 and 589, adult males of Jamaicana flava, N. Sp., Caudell. 



430, a nymph and 560, an adult male of Jamaicana unicolor, 

 Brunner. 



416, 585, 586, 587, four adult males of Jamaicana suhguttata 

 Walker. 



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