494 D. H. WENRICH 



determined by Carothers, and the present observations corrob- 

 orate those made by her. 



2. Synapsis consists in a side-by-side union of leptotene 

 threads, which parallel association persists until the breaking 

 up of the spireme into its constituent segments and the pro- 

 duction of tetrads by the formation of the secondary longitudinal 

 split. 



3. The process of parallel conjugation appears to begin at 

 the proximal ends of the leptotene threads, as was found in 

 Chorthippus. 



4. The great variety of metaphase shapes for the same tetrad 

 appears to be correlated with variations in the extent and char- 

 acter of the movements of the chromatids with reference to each 

 other in the earher tetrad stages. 



5. At the point of spindle fiber attachment (synaptic point) 

 in the pairs of atelomitic chromosomes there occurs a transverse 

 constriction, or cleft, similar to those found for the atelomitic 

 chromosomes of Chorthippus. 



6. Chromosomes 4 and 8 (plate 2) each bears near one end a 

 cluster of granules which is thought to be homologous with the 

 chromomere-vesicles seen in Chorthippus and other grasshoppers. 



III. DISCUSSION 



On the basis of the foregoing observations it seems worth 

 while to discuss briefly the following topics: (A) Synapsis, (B) 

 pre-reduction vs. post-reduction, (C) chromosome organization. 



A. Synapsis 



In considering the subject of synapsis it may be well first to 

 summarize the evidence gained from the study of Chorthippus 

 and Trimerotropis, together with that previously recorded for 

 Phrynotettix, and then to compare these evidences with the 

 results recorded by others who have studied Chorthippus (Steno- 

 bothrus). An extended discussion of the literature on synapsis 

 would be superfluous in view of the consideration given the 

 subject by McClung ('14), Robertson ('16) and the writer ('16). 



