2 THOS. H. MONTGOMERY jr., 



my specimens belonged to the genus Pentatoma, sensu strictiori. 

 Certainly however they are members of the family Pentatoniidae. 

 Another member of this family was also studied for comparison, and 

 in it every process of spermatogenesis was found to be exactly the 

 same as in the preceding; this second genus was either Tropicoris, or 

 a closely-allied one. The testicles of these two genera were preserved 

 by me at a time when I had not expected to make a special study 

 of spermatogenesis, with the result that I did not undertake a careful 

 identification of the species ^). But as I examined preparations of their 

 testicles I was immediately struck with the small number of chromo- 

 somes, and the large size of all the cellular elements, and so resolved 

 to complete a study of the reduction phenomena. The spermatocytes 

 in Pentatoma have a size nearly equal to those of the salamander, 

 and on account of the smaller number of chromosomes are really more 

 favorable objects for study. These bugs are nearly cosmopolitan, and 

 may be found in abundance in the warm season of the year, on which 

 account they should soon become desired objects for cytological in- 

 vestigations. 



I had but a small amount of material, not being able to procure 

 more during the winter mouths spent in this study ; the testicles of 

 two specimens of Pentatoma, and two of Tropicoris, were my sole 

 material. One testicle of Pentatoma was fixed in Hermann's fluid 

 (platinum chloride, osmic and acetic acids) and stained with Her- 

 mann's saffranine, gentian-violet mixture (as given by him in: Archiv 

 mikr. Anat., 1889). This furnished a preparation of great beauty and 

 sharp contrast of coloration; on thin sections of this testicle most 

 of these observations were made. The other testicles were fixed in 

 aqueous solution of corrosive sublimate, which proved a poor method 

 and produced a marked distortion of the cells nearest the periphery 

 of the testicle ; in an aqueous solution of corrosive sublimate, 100 parts, 

 with 5 parts of glacial acetic acid, which furnished a fixation of more 

 value than the preceding; and in Boveri's picro-acetic acid, which, 

 however, was hardly of as much value as the sublimate-acetic mixture. 

 The preparation fixed with Hermann's fluid was far superior to any 

 of the others, though throughout my observations the other prepar- 

 ations were consulted for comparison. Besides the stain of Hermann, 



1) Since the preceding was written, I have examined a number of 

 genera of this family, and conclude that the two species here mentioned 

 belong to the genus Euchistus, 



