WENRICH: spermatogenesis of PHRYNOTETTIX MAGNUS. 101 



would be unnecessary. Robertson says he believes that the unequal 

 tetrad in Tettigidea -parvipennis has arisen by a loss at the distal end. 

 And he finds in other individuals an homologous pair each member 

 of which is equivalent to the larger member of the unequal pair. 

 This is just the condition that is presented by B in my material. And, 

 furthermore, by analysis of the pachytene and postspireme stages, I 

 am able to say just what part has been lost. 



Another striking analogy between my observations and those of 

 Robertson occurs in connection with the larger unequal pair that he 

 has found in Acridium granulatus. He finds in some individuals a 

 small equal pair and in two individuals an homologous unequal pair, 

 the smaller component of which corresponds to either of the two 

 elements of the equal pair. This, again, is precisely the relationship 

 between types Ci and C2 in Phrynotettix. Here, too, we both failed 

 to find the other possible combination, namely, that of a pair of the 

 larger conjugants. These striking similarities lead me to think that 

 the elements described by Robertson may be explained in the same 

 way that I have explained them in Phrynotettix. If such be the 

 case, then the various assumptions as to doubling and "sesquiva- 

 lent" chromosomes will be unnecessary. I believe, further, that 

 without a doubt the unequal tetrads described by Robertson do 

 divide reductionallv in the first maturation division, but that the 

 spindle-fiber attaches at the distal and not at the proximal end; and, 

 furthermore, that there is a very good chance that the other chromo- 

 somes may behave as does chromosome-pair A in Plirynotettix, and 

 therefore divide equationally, as it does. 



Of recent works on Hemiptera, the most interesting from the stand- 

 point of synapsis are the papers by Montgomery, Wilson, and Korn- 

 hauser. Montgomery ('11) advocated telosynapsis for many years, 

 but in this late paper, in which he described the spermatogenesis of 

 Euschistus, he concludes that pairing is by a process of parasynapsis. 

 I believe it to be a highly significant fact that Montgomery, at the 

 end of his very active career as a cytologist, and with his wide ex- 

 perience back of him, should reverse his former position on the subject 

 of synapsis and should find parasynapsis in this insect, which he had 

 studied and reported on at an earlier date ('01). He says (p. 743): 

 " In the growth period through the pachytene stage there is no longi- 

 tudinal splitting, for what I had previously ('01) interpreted as such, 

 I now find to be the line of conjugation .... Frequently at certain 

 points along a geminus the chromatin granules appear accurately 

 paired. But this does not appear until a rather advanced stage of the 



