CHROMOSOMES IN THE SPERMATOGENESIS OF THE HEMIPTERA HETEROPTERA. I(j7 



EXPLANATION OF THE PLATES. 



All the ligures have been drawn by the author with the camera luoida at the level of the tese of the microscope, 

 aud the reproductions are the size of the originals. Figs. 1-68, 94-106 and 126-1^3 are drawn at a magnification of about 

 2,080 diameters, all the others at a magnification of about 2,480 diameters. Lateral views of the first maturation spindles 

 are placed the length of the plate, of the second maturation spindle the width of the plate, which enables one to distin- 

 guish them at a glance. The following abbreviations have been employed : 



Di, diplosome. 



Mo, monosome. 



PI, plasmosome (true nucleolus). 



The diplosomes are paired elements, and when their separate components can be distinguished, they are lettered Di 

 and di respectively ; in case there is more than one pair of them to a cell a number is placed after letters, viz., Di. 1, di. 1 

 would be one pair and Di. Z, di. 2 a second pair ; the capital letter is used for the small component of a pair and the small 

 letter for the larger one in those cases where they differ in size. If there is a single monosome present it is lettered 

 simply Mo, but if two they are lettered Mo. 1 and Mo. 2. Single letters denote autosomes, a capital and a lower case 

 letter of the same kind (as A and a) marking the components of a pair ; if the capital and the small letter are separated 

 by a comma, as "^1, «,'' a pair of correspondent ones is denoted ; but if a capital is followed by a small letter enclosed in 

 parentheses, as " J («)," it is indicated that but one of the elements is present, i. e., either A or a. 



Some of the figures are redrawings of cells previously figured by me, and in such cases this is noted by the date of 

 the paper where the particular cell was first illustrated followed by the number of the original figure, all this being 

 enclosed in parentheses, as " (v. 19016, Fig. 2)." 



Plate IX. 

 Figs. 1-14, Euscliistus variolariiis. 

 Figs. 1-4, sperraatogonic monasters (with Fig. 1, v 19016, Fig. 2). 

 Fig. 5, nucleus in synapsis stage. 



Figs. 6-9, successive prophases of the maturation mitosis, the last two showing all the chromosomes. 

 Fig. 10, first maturation monaster. 

 Figs. 11, 12, second maturation monasters. 

 Figs. 13, 14, chromosomes of two spermatids. 



Figs. 15-22, Emchidus tridigmus. 

 Fig. 15, spermatogonic monaster. 

 Fig. 16, nucleus of synapsis stage. 

 Fig. 17, pole view of first maturation spindle. 

 Fig. 18, lateral view of the same. 



Fig. 19, pole view of a plate of daughter elements before their arrangement in the spindle. 

 Fig. 20, second maturation spindle. 

 Figs. 21, 22, chromosomes of two spermatids. 



Figs. 23-27, Podisus spinosus. 

 Fig. 23, spermatogonic monaster (v. 19016, Fig. 27). 

 Fig. 24, nucleus of late synapsis stage. 

 Fig. 25, oblique lateral view of first maturation spindle. 

 Fig. 26, pole view, second maturation spindle. 

 Fig. 27, lateral view of the same stage. 



