480 Alice M. Boring 



results were Heidenhain's iron haematoxylin, either without a 

 counterstain, or with a slight tinge of orange G, thionin without a 

 counterstain, and Auerbach's combination of acid fuchsin and 

 methyl green. With iron haematoxylin, the long method gave the 

 best results. Preparations in this stain furnish the best outlines 

 for camera drawings, but forw^ork in spermatogenesis, there is the 

 disadvantage that it often stains plasmosomes and chromosomes 

 alike. Thionin has proved a valuable stain for distinguishing 

 between chromatic material and plasmosomes. With this mate- 

 rial the best results are gained by leaving the slides in the stain 

 from one to five minutes, rinsing off with water, and differen- 

 tiating under the microscope with 95 per cent alcohol. The 

 basichromatin holds the stain as a navy blue or dark purple, depend- 

 ing upon the material; while the plasmosome and oxychromatin 

 either take a very pale blue, or hold no color at all. The Auer- 

 bach stain also gives differentiation between basi and oxychro- 

 matin, the odd chromosome standing out bright green in the rest 

 stage against the pink spireme or scattered oxychromatin. 



OBSERVATIONS 



MembraaJcs 



In the Membracidae, the testes are situated ventrally, near the 

 anterior end of the abdomen. They are white in color, and each 

 follicle is round. Such ripe spermatozoa as are present are found 

 near the duct and the spermatogonia are situated on the opposite 

 side. The rest of the follicle is filled with the intermediate stages, 

 grouped into cysts containing cells in about the same stage. The 

 succession of these stages is rather difficult to follow in the Mem- 

 bracidae, because the follicles are spherical and no one longitudinal 

 section gives all of the stages. The only way to trace the develop- 

 ment is to find cysts with most of the cells in one stage and a few 

 in transition to the next stage. In this way, the links between the 

 stages can be filled in. In the eight species from which my mate- 

 rial was obtained, the general course of development is very simi- 

 lar, with only here and there a striking difference. I shall there- 



