660 ' C. E. McCLUNG 



chromosome number for only the latter where he found 3 1 . Buch- 

 ner ('09) however also gives 31 for Decticus, while Vejdovsky 

 ('12) reports but 23 for the same species. Taking these results 

 at their face value it is evident that in the Locustidae there is an 

 unequal diploid chromosome group with an unpaired accessory 

 chromosome and all the other characters that have been considered 

 in connection with the Acrididae. 



3. Gryllidae. Careful detailed studies of the chromosome rela- 

 tions in the Gryllidae are few. Baumgartner ('04) reports 29 

 chromosomes in Gryllus assimilis and 21 in G. domesticus. This 

 latter number was also found in the same species by Gutherz 

 ('07) and in G. desertus by Brunelh ('09). Buchner ('09) and 

 Voinov ('04) have both studied G. campestris but without giving 

 any results of value on chromosome relations. Gryllotalpa has 

 been studied by Buchner, Payne, vom Rath and Voinov, Vom 

 Rath ('91) reported at length on the spermatogonia of this ani- 

 mal and his figures were widely copied, but it is very evident that 

 he was fundamentally in error regarding the most essential part 

 of his work. He announces 12 as the diploid chromosome num- 

 ber but the internal evidence and the results of other investiga- 

 tors show that this is really the haploid condition, 



4. Phasmidae. Studies on the Phasmidae are not numerous. 

 Practically the only ones from a modern standpoint are those of 

 de Sinety and Jordan and in the former case the work is lacking 

 in needed detail, De Sinety finds 36 chromosomes in Leptynia 

 with a typical accessory chromosome joined to a tetrad in the 

 spermatocyte. If this be counted a separate chromosome for 

 each univalent part there is an odd number. Jordan ('08) seems 

 to determine definitely the number 35 in Aplopus. Since de 

 Sinety's enumerations are evidently not made with great care it 

 is possible that in Leptynia the same number is present. Dixip- 

 pus and Menexenus were also studied by the French investigator 

 but no chromosome counts are given. 



5. Blaitidae. Of the cursorial Orthoptera the Blattidae have 

 been most studied. Morse ('09) investigated four genera and 

 found in Blatta, Leucophaea and Stylopyga a diploid group of 

 23 paired elements of typical Orthopteran behavior, while in Peri- 



