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 Tryxalinae. 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 localities, as follows: Chortophaga viridifasciata 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- 
telra 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, 
