OF THE GERM CELLS OF METAZOA. 



169 



somes and one bivalent chromatin nucleolus ; Fig. 78 is a pole view, but in it those 

 elements which appear dumbbell-shaped are seen from the side. 



15. Ariasa sp. 



Of this undetermined species, which was collected for me at Berryessa in California 

 I examined nine testes. 



The resting spermatogonium shows two chromatin nucleoli (PI. II, Fig. 79, iV! 2) 

 which arc comparatively large arid rather loose in texture, generally irregular in outline, 

 occasionally attached to the true nucleolus (N), and more or less central in position. 



In the monaster stage of the spermatogonia (Fig. 80) are twenty-two chromatin 

 segments, namely, twenty larger chromosomes and two smaller chromatin nucleoli {N. 2). 



In the synapsis the chromosomes unite to form ten bivalent ones, and the chromatin 

 nucleoli to form one bivalent one. In the rest stage of the spermatocytes (Fig. 81) the 

 chromatin nucleolus {N. 2) is seen to be somewhat elongate in form, is peripheral in 

 position, and not attached to the true nucleolus (N). 



In the monaster stage of the first maturation division are eleven bivalent elements, 

 of which the smallest is the chromatin nucleolus (JSf. 2, Fig. 82) ; in this figure we do 

 not have strictly pole views of all the chromosomes. 



Fig. 83 shows four of the bivalent chromosomes on lateral view, in a paratongential 

 section of a cell in the stage of the first maturation monaster. It is given here because 

 it is the clearest case I have noticed in any Hemipteron of the quadripartite nature of 

 these chromosomes, for while the transverse split may generally be seen at this stage, the 

 longitudinal split is generally hidden. The poles of the spindle (not in the plane of 

 this section, but seen in the next one to it) are situated at the upper and lower portions of 

 the figure respectively ; and it is hardly necessary to add that the first maturation division 

 coincides with the plane of the transverse split, the second with the plane of the longi- 

 tudinal split. 



16. Metapodius terminalis Dal]. 



Eleven testes were studied of this species, which is very favorable on account of the 

 large size of the cells ; one should examine testes from individuals taken in June or early 

 July, before the time of copulation. 



In the rest stage of the spermatogonia (PI. II, Fig. 84) are two chromatin nucleoli 

 (JSf. 2) of very small size and smooth outlines, generally close together on the surface of 

 a, true nucleolus ( TV). 



In the spermatogonic monaster- (Fig. 85) art; twenty-two chromatin segments, of 

 which the two smallest are chromatin nucleoli (N. 2) and easily recognizable, 



