116 CHROMOSOMES IN THE SPERMATOGENESIS OF THE HEMIPTERA HETEROPTERA. 



than half the volume of the other five, and sometimes it does not appear dumhell- 

 shaped." 



17. Chariesterus antennator Fabr. 



There were no spermatogonic divisions suitable for study. 



Growth Period. — In the synapsis and later stages (a complete rest stage was not 

 observed) there are in each nucleus two compact, safraninophilous bodies, close to the 

 nuclear membrane ; a plasmosome was not f(L)und. The smaller of these bodies (J)i, 

 di, Plate XI, Fig. 126) is regularly constricted, and by analogy with the relations in 

 other members of the family is probably a bivalent diplosome, and its later history is 

 in accord with this assumption. The larger safraninophilous body is longitudinally 

 split (Mo), and corresponds to the monosome of tlie later stages. 



First Maturation Divishm. — Pole views of the chromosomal plate show in most 

 cases (14 out of 18) 13 elements (Fig. 127). The central is always the smallest, and 

 very likely is a bivalent diplosome [Dl, di) ; its two components are of approximately 

 the same size. Around it is a circle of 11 autosomes, and just outside of the latter an 

 element {Mo), the monosome, lying with its long axis in the ec^uator while the autosomes 

 are perpendicular to it. In 4 out of the 18 clear pole views examined there appeared 

 to be 14 elements (Fig. 128) ; these are to be interpreted, as in Harniostes, that one of 

 the bivalent autosomes has its univalent components precociously separated ; and 

 in all such cases illustrated by Fig. 128 there lie near each other two elements of 

 equal volume {31), each of whirh is of less depth than any other of the autosomes. The 

 autosomes and the diplosome divide reductionally, the monosome through the plane 

 of its longitudinal split (Fig. 129). 



Second Maturation Division. — Here there are always 13 elements (Fig. 130). 

 The smallest is a diplosome {di), 1 1 others are autosomes, and all these divide equa- 

 tionally. But the monosome passes without division into one of the spermatids. 

 This is shown distinctly in two daughter chromosomal plates of the early anaphases 

 of the same cell, the drawings made accordingly at different focu.sses (Figs. 131, 132); 

 in each there is a diplosome recognizable by its very small size, but only one shows 

 the monosome {Mo, Fig. 131). And in later anaphases on lateral views (Fig. 133) are 

 to be seen regularly an element, the monosome, in one spermatid that is not found in 

 the other. Half the spermatids receive, accordingly, 13 elements, and half 12. 



Judging from the relations during these maturation mitoses the number of chro- 

 mosomes in the spermatogonia would ber^l monosome, 2 diplosomes, 22 autosomes, a 

 total of 25. 



Literature. — My preceding observations (19016) were correct, and tluiugh 1 did 

 not distinguish a monosome in the growth period of the spermatocytes, I called atten- 



