DAVIS: SPERMATOGENESIS. 63 



reduction in Weismann's sense. Otte agrees with McClung, that 

 during the growth period of the primary spermatocyte the accessory 

 chromosome forms a spireme, but thinks that it divides transversely 

 during the second division. Otte (:06'*) also gives a detailed account 

 of the metamorphosis of the spermatid. 



In a recent paper Gutherz (:07) confirms, in the main, Baumgartner's 

 observations on the accessory chromosome in Gryllus. 



II. Material and Methods. 



The following investigations are based on material from seven 

 species of Orthoptera belonging to two families, although a number 

 of other species have been examined from time to time for com- 

 parison. Six species of the Acrididae have been selected for descrip- 

 tion, as follows: Dissosteira Carolina, Arphia tenebrosa, Hippiscus 

 tuberculatus and Chortophaga viridifasciata, belonging to the sub- 

 family Oedipodinae; Melanoplus femoratus, belonging to the 

 subfamily Acridinae; and Stenobothrus curtipennis, belonging to 

 the subfamily Tr>^alinae. In addition an account is given of the 

 spermatogenesis of Steiroxys trilineata, a locustid. 



The material was obtained mostly from adult individuals collected 

 in three locahties, as follows: — Chortophaga \'iridifasciata and Hip- 

 piscus tuberculatus at Cambridge, Mass.; Dissosteira Carolina, Mel- 

 anoplus femoratus, and Steiroxys trilineata at Pullman, Wash., while 

 Stenobothrus curtipennis was collected at Cambridge, Mass., Pullman, 

 Wash., and Torrington, Conn. 



It has seemed best to describe the spermatogenesis of one species 

 as completely as possible, and in the other forms, in order to avoid 

 needless and tiresome repetition, to consider only points which are 

 of especial interest. The most complete account is given for Dissos- 

 teira Carolina, not because the material was more favorable than in 

 some of the other species, but because it is a common form and is 

 considered representative of the subfamily to which it belongs. 



In all cases the testes were dissected out in a 0.6% salt solution 

 and placed at once in the fixing fluid. A number of fixing fluids were 

 tried, namely: Hermann's platino-aceto-osmic, Flemming's chromo- 

 aceto-osmic (strong formula), Worcester's formol-sublimate-acetic 

 mixture, and Zenker's bichromo-sublimate-acetic mixture. It was 

 found that much the best fixation was obtained with Hermann's 

 fluid; consequently this was later used almost exclusively, although 

 Flemming's fluid was used in a few cases. In using both these fluids, 



