A STUDY OF THE GERM CELLS OF CERTAIN 

 DIPTERA, WITH REFERENCE TO THE HETERO- 

 CHROMOSOMES AND THE PHENOMENA OF 

 SYNAPSIS 



BY 



N. M. STEVENS 

 With Four Piates 



INTRODUCTION 



In connection with previous work on the spermatogenesis of 

 the Coleoptera ('05, '06), the germ cells of the common fruit-fly, 

 Drosophila ampelophila, were examined in the autumn of 1906. 

 The difficulties encountered in handling this material led to the 

 study of the spermatogenesis of several other flies. The results 

 will be presented in accordance with the following scheme: 

 Calyptrate Muscidae. 

 Muscinae. 



1 Musca domestica. 



2 Calliphora vomitoria. 



3 Lucilia caesar. 

 Sarcophaginae. 



4 Sarcophaga sarraciniae. 

 Anthomyiinae. 



5 Phorbia brassica. 

 Acalyptrate muscidae. 



6 Scatophaga palHda. 



7 Tetanocera sparsa. 



8 Drosophila ampelophila. 

 Syrphidae. 



9 Eristahs tenax. 



METHODS 



With this material it was found that the best results could be 

 obtained from fresh tissue mounted in Schneider's aceto-carmine. 



The Journal of Experimental Zoology, vol. v, no. 3 



