84 E. L. SHAFFER. 



while it covered a large number of species, was concerned only 

 with chromosome counts, and especially with reference to the 

 sex chromosomes. In only two species of beetles has there been 

 anything like a detailed study of the chromosomes in synapsis, 

 Voinov (1903) on Cybister roselii and Schafer (1907) on Dytiscus 

 marginalis. Both these authors after a detailed study of the 

 growth stages of the spermatocytes describe parasynapsis, 

 while Miss Stevens claims telosynapsis in the forms she studied. 



FIG. i. Single testis of Lachnosterna (side-View), with its efferent duct. 



The material used in this study was fixed in Flemming's, Her- 

 mann's, Bouin's, Gilson's and Carnoy's fixing fluids. In general, 

 the Flemming and the Hermann material was best for the growth 

 stages of the spermatocytes, while the Bouin material was best 

 for the chromosomes. Iron-haematoxylin, with and without a 

 counterstain, was employed entirely for staining. Aceto-carmine 

 smears were valuable in checking the observations on the fixed 

 material. All the testes, except those of L. ftisca, were taken 

 v from the adult beetles. The material was gathered in midsummer 

 and showed all stages from spermatogonia to ripe spermatozoa. 

 In the case of L. fusca, the adult testes showed few favorable 

 stages and it was necessary to study the larval gonads. 



C. DESCRIPTION OF TESTES AND SERIATION OF STAGES. 



The testes consist of twelve mushroom-like bodies, three pair 

 in each side of the abdomen. Each testis has its duct (Figs. 

 i and 2) and the ducts from each group of testes unite to form 

 two larger ducts; these four larger ducts in turn unite to form 

 the single median vas deferens. 



