460 E. ELEANOR CAROTHERS 



very well be different. The solution in both instances could only 

 be obtained by a comparative analysis of the chromosomal con- 

 stitution of given pairs of grasshoppers and of their offspring. In 

 any case, in order to complete the parallelism between the be- 

 havior of the chromosomes and Mendelian phenomena, it was 

 necessary to trace the behavior of the heteromorphic chromo- 

 somes from parents to offspring. 



II. MATERIAL AND METHODS 



Since all of the species used in my 1917 work occur only in the 

 western half of the United States, the hope was then expressed 

 that Circotettix verruculatus, whose range extends to the eastern 

 part of the country, might be equally favorable. This expecta- 

 tion was justified, and combined cytological and genetical work 

 was undertaken on this species. The stock was obtained from 

 near Manchester, New Hampshire, July 29, 1918. Collecting 

 during the last week of July, one obtains both adults and nymphs.^ 



It is necessary to obtain the females as nymphs to insure their 

 being virgin. Males and females were kept in separate cages 

 until about September 1, when individual matings were made 

 up. After eggs had been laid both parents were killed and the 

 gonads fixed; the testes in strong Flemming, the ovaries in picro- 

 formol-acetic. 



Of eighteen matings, one or the other of the parents died in 

 six, and these cages were discarded ; four of the twelve remaining 

 cages contained no eggs, due perhaps to the exhaustion of the 

 ovaries of the females before the matings were made up (some of 

 the females had laid at least ten days previously). The remain- 

 ing eight matings gave 138 offspring. Fifty-one was the largest 

 number obtained from one pair. Eggs from three pods hatched 

 from this mating. 



Twenty-eight male offspring from five of the matings have 

 been studied cytologically, and it is believed that they furnish 

 sufficient evidence as to the point under consideration. 



2 It is intended to give details of the rearing and postembryonic development 

 of C. verruculatus in a separate paper. 



