S pertiiatogenesis 49c 



chromatin becomes scattered and diffuse (Fig. 166). The first 

 spermatocyte shows the odd chromosome as a medium-sized body, 

 eccentric in the plate of 12 chromosomes (Fig. 167), and not divid- 

 ing in metakinesis (Fig. 168). In anaphase, it lags behind the 

 others (Fig. 169). The two large chromosomes of the spermato- 

 gonia have fused into a single large one in the first spermatocyte 

 {a in Fig. 167), and this keeps its individuality in the second sper- 

 matocytes {a in Figs. 170 and 171). Half the second spermato- 

 cytes have 12 chromosomes, and half 11. The spermatids all 

 have the chromatin nucleolus, and half of them the odd chromo- 

 some (Figs. 174 and 175), as in Chlorotettrix. 



Diedrocephala mollipes 



This species resembles Diedrocephala coccinea in shape, but 

 not in color, being bright green instead of red and green striped. 

 Its spermatogenesis is also similar (Figs. 176 to 185), but the 

 cells and chromosomes are smaller (cf. Fig. 177 and 167). They 

 both have the same number ot chromosomes, 12, but Diedrocephala 

 mollipes has no one chromosome markedly larger than the others. 

 The spermatids have both a chromatin nucleolus and an odd 

 chromosome. 



Phlepsms irrotatus 



The spermatogonia! plate contains 15 chromosomes, two larger 

 than the others {a^ and a^, Fig. 186). These are represented by a 

 in the first spermatocyte (Fig. i88a) and also in the second sperma- 

 tocytes (Figs. 191 and 192, a). The growth period shows the odd 

 chromosome (x) as a round body with even contour (Fig. 187). 

 The univalent chromosorne x has the peculiarity here that it never 

 comes to lie in a flat plate with the other chromosomes in the first 

 spermatocyte division, as is indicated in Fig. 189. To get all 8 

 chromosomes, the equatorial plate must be drawn at two diff^erent 

 foci (Figs. 1 88 a and i88b). The odd chromosome always precedes 

 the others to the pole (Fig. 190), never taking the lagging position 

 characteristic of the species previously described. We have noted 

 that this sometimes takes place in other forms (Vanduzea arcuata, 

 and the three species of Ceresa), but Phlepsius is the first form 



