SPERMATOGENESIS IN PARATETTIX. 263 



lengths of the wings and pronotum are not inherited but are 

 closely correlated with the length of time required for the animal 

 to reach maturity. These grasshoppers have furnished the 

 material for the present paper. 



The work on the cytological constitution of the germ-cells of 

 Paratettix has been undertaken for the purpose of discovering 

 whether or not the microscope will reveal any differences in 

 the germ-cells of very closely related forms which may be corre- 

 lated with the differences in the color pattern. The spermato- 

 genesis of only one form (Paratettix leuconotus-leucothorax} 

 is given here. Paratettix leuconotus-leucothorax is a hybrid, 

 obtained by crossing P. leuconottis with P. leucothorax (or by 

 the interbreeding of two hybrids, one being a hybrid of leuconotus 

 with some other form and the other a hybrid of leucothorax 

 with some other form). No attempt has been made to show any 

 relation between the structure of the germ-cells and the somatic 

 structures. This will be discussed in a later paper. 



The chromosomal complex of the spermatogonia of Para- 

 tettix leuconotus-leucothorax consists of thirteen rod-shaped 

 bodies which may be divided into two groups one group con- 

 sisting of four larger chromosomes and the other of nine smaller 

 ones. Neither the larger nor the smaller chromosomes form 

 equal sized pairs as Sutton has found in Brachystola magna and 

 which is so frequently described for the Hemiptera and is ap- 

 parently characteristic of all Diptera. All of the large chromo- 

 somes and one of the small ones are bent rods or slightly U- 

 shaped, but the other eight are almost straight. No one of 

 these chromosomes has been surely identified as the accessory. 

 However, in the early prophases there is always present a mass 

 of chromatin which has a more compact consistency and stains 

 more intensely than the remainder of the chromatin (A, Fig. i). 

 This mass has not been identified with any chromosome nor is 

 it associated with a vesicle as described by Carothers for Arphia 

 simplex. There appears to be no difference in the staining 

 capacity nor in the compactness of the chromosomes in the late 

 prophases (Fig. 2). 



The spermatogonial spindle is long and slender, and has fine 

 but distinct fibers which converge at the poles. The centrosome 



