496 Alice M. Boring 



where this position is invariable. The second spermatocytes con- 

 tain 8 and 7 chromosomes (Figs. 191 and 192). The spermatids 

 all contain the chromatin nucleolus (Figs. 195, n, and 196, n) and 

 half of them, an odd chromosome (Figs. 195 and 196, x). 



Agallia sanguinolenta 



No spermatogonia! plates were found in this form. The odd 

 chromosome appears as usual in the growth period (Fig. 197). 

 There are 11 chromosomes in the first spermatocyte (Fig. 198), 

 and II and 10 in the second (Figs. 200 and 201). The odd chro- 

 mosome does not divide in the first spermatocyte metakinesis 

 (Fig. 199), but passes to one pole after the other chromosomes in 

 anaphase (Fig. 206). The spermatids all contain a chromatin 

 nucleolus, and half of them, the odd chromosome (Figs. 203 and 

 204). Figs. 205 to 207 are drawn from aceto-carmine preparations 

 at the same magnification as Figs. 197 to 204. 



Cercopid^e 



The testes of the Cercopidae are situated near the posterior end 

 of the abdomen. They are white in color, and each follicle is 

 round, with a comparatively long duct joining it to the vas deferens. 

 The material comprises four species, and the spermatogenesis of 

 none of them resembles very closely that of the species studied by 

 Stevens ('06b). 



Clastoptera obtusa 



Thi's species was found on the alder at Cold Spring Harbor. 

 The resting spermatogonium stains very lightly and has a plasmo- 

 some (Fig. 208). In preparing for division, the chromatin forms 

 a spireme, which becomes more dense, and then segments (Fig. 

 209). There are 15 chromosomes in the spermatogonial equa- 

 torial plate^all of about the same size (Fig. 210). The division is 

 longitudinal as usual (Figs. 211 and 212). After the telophase, 

 the chromosomes soon become joined by linin connections (Fig, 

 213), form a compact spireme in early synapsis (Fig. 214), a dense 

 mass in the contraction stage (Fig. 215) and a spireme loosely 

 wound on itself in postsynapsis (Fig. 216). The odd chromosome 



