492 Alice M. Boring 



mosomes may really be but one. Other evidence for the univa- 

 lence of one chromosome is its occasional appearance in early 

 metaphase of the first spermatocytes when it has not yet assumed 

 the dumb-bell shape (Fig. 129), and a few second spermatocyte 

 metaphases where it apparently does not divide (Fig. 133). If it 

 does not divide in the second spermatocyte division, the second 

 spermatocyte spindle should always appear as it does in Fig. 133 

 rather than as in Fig. 132, unless the odd chromosome is usually 

 in the center surrounded by the other chromosomes. That this 

 probably is true is indicated by several cases like Fig. 135, the two 

 anaphase groups of one second spermatocyte spindle, a having 9 

 chromosomes and b 10. There is a space in a corresponding to 

 the chromosome marked x in h. This evidence is anything but 

 satisfactory, but the possibility of such an exception to the general 

 rule that the odd chromosome divides in the first spermatocyte 

 division, is too interesting a fact to leave unmentioned. Here 

 again one large chromosome in the first spermatocyte (Fig. 126) is 

 represented by two in the spermatogonia (Fig. 123, a^ and a^_), and 

 by one in the second spermatocyte (Fig. 131, a). Fig. 127 shows an 

 occasional first spermatocyte with 1 1 chromosomes, implying 

 a delay in the fusion of one pair. Here we find the chromatin 

 nucleolus in all the spermatids (Fig. 136). 



'J as SI dee 



The testes of the Jassidae are pale yellow in color, and there- 

 fore very easy to dissect out. The follicles are about three times 

 as long as broad; this makes it easier to trace the development 

 from stage to stage than in the Membracidae. My material 

 includes six species, four of them caught at Cold Spring Harbor 

 in July, and the other two, Agallia sanguinolenta and Phlepsius 

 irrotatus, at Bryn Mawr in October. 



Chlorotettrix unicolor and C. vividus 



This material was fixed and preserved as belonging to one 

 species, but study of the sections showed two different reduced 

 numbers of chromosomes, 11 and 9. This led to a careful com- 



