298 FERNANDUS PAYNE 



C. Discussion of chromosomes 



In the preliminary paper it was stated that the chromosome 

 combination in Gryllotalpa borealis could be interpreted in one 

 of three ways; first, as an unequal pair of idiochromosomes and 

 a supernumerary; secondly, as a triad group similar to that of 

 Conorhinus, Fitchia (Payne '09) or Thyanta (Wilson '10) with 

 the exception that in Gryllotalpa the grouping occurs in the first 

 division instead of the second, and that the two chromosomes 

 which go to the female producing pole do not behave as a unit; 



<|»> •"£ \fc c ^ 





*!{Of»>t0 G ■ 



H 



Text fig. 5 Gryllotalpa vulgaris from Freiburg. A, B, C, D, spermatogonial 

 divisions, 12 chromosomes; E, first spermatocyte division, six chromosomes; 

 F, G, two figures from the same cell, first spermatocyte division, side view; H, 

 a fairly typical tetrad in the first spermatocyte division. 



thirdly, as an unequal pair of idiochromosomes and an accessory 

 chromosome. At that time I discussed the three possibilities, 

 discarding the first as there was no evidence in support of it. 

 The single unpaired chromosome is regular in its behavior and 

 has a definite relation to sex production, always passing into the 

 female-producing spermatozoon. Between the other two possi- 

 bilities, I did not state my preference. I gave the facts in sup- 

 port of each and left the reader to choose for himself. At the 

 present time, if I were to make a choice, I should select the 

 second. Not because the evidence in itself favors it more than 

 the third, but because this interpretation makes this combina- 



