1;^-!: CHROMOSOMES IN THE SPEKMATOGENESIS OF THE HEMIPTERA HETEROPTERA. 



(Fig. 2G8), and that showed 10 elements. But from its unipartite appearance in the 

 spindle, and from its situation a little out of the plane of the autosomes, there can he 

 little doubt that the monosome passes undivided into one of the spermatids. 



Literature. — My former description (1901) was incorrect in concluding 20 to be 

 the normal number of chromosomes, and in supposing the allosomes of the growth 

 period to be a pair of diplosomes. Also I did not describe the second maturation 

 mitosis. 



37. LiMNOTRECHUS MARGINATUS Say. 



The spermatogenesis is on the whole very similar to that of the preceding species. 

 There were no spermatogonic divisions on my slides. 



Groiiih Period. — There is a monosome, which in the rest stage [Mo, Fig. 269, 

 Plate XIII) is longitudinally split; it may be nearly spherical, but more usually is 

 elongate Avith the split along its length ; further, it is usually separated from the plas- 

 mosome [PI). These constitute the main difierences from Hijgotrechus. 



First Maturation Division. — There are 10 large tetrads, the autosomes, and 1 small 

 dyad, the monosome {Mo, Figs. 271, 272). All of them divide, the monosome 

 equationally. 



Second Maturation Division. — There are also 10 autosomes and the half of the 

 monosome (Fig. 274), the latter recognizable upon pole view by its lesser depth. All 

 the autosomes divide, but the monosome {Mo, Fig. 273) remains rounded, is placed 

 usually a little nearer one spindle pole than the other, and therefore probably passes 

 undivided into one of the spermatids. 



Literature. — My preceding account (1901/>) was very brief, and I supposed a pair 

 of diplosomes to be present. 



GAPSIDM 



38. Calocoris rapidus Say. 



Spermatogonic Division. — There was onl^' one clear pole view (Plate XIII, Fig. 

 275), and that showed exactly 30 elements. 



Gro'wth Period. — Throughout this period there is a deep-staining, rod-like body 

 close against the nuclear membrane, which on profile gives the effect of a crescent. 

 In the synapsis (Fig. 276, Mo. 1) it is more or less ovoid, but it later assumes the form 

 of a bent rod {Mo. 1, Fig. 277) and during all the stages except the earliest shows a 

 well-marked longitudinal split. In the later stages this body has usually the form of 

 two bent rods, which may be parallel, or slightly divergent when the space between 

 them is the longitudinal split. This is tlie larger monosome of the spermatocytes, as 

 will be demonstrated by its later history. Though always prominent in the nucleus 



