LINKAGE OF CHROMOSOMES. , 1 69 



some, he believes there results twenty-three, the number normal 

 for TruxalincB a subfamily of the Acrididce. It was at his sug- 

 gestion that I undertook to determine if Jamaicana which I 

 found to have these V-shaped chromosomes showed the same 

 phenomena. 



In my material the multiple is likewise apparently formed by 

 the union of two of the autosomes. As has been done by others, 

 I numbered and paired the chromosomes according to size, 

 calling the unpaired accessory which is the largest chromosome 

 in the complex, No. 18, and grading the others down from that. 

 I at once found two autosomes of unequal length. No. 16 and 14, 

 without mates as well as the very noticeable V. Since the arms 

 of the V are unequal, and correspond in size as well as length to 

 the unmated rods, I believe No. i6 is the mate of the long arm 

 of the V, while No. 14 mates with the short arm of the multiple 

 (Figs. 30-36). The sex chromosome is very prominent and is 

 often seen in close proximity to the multiple throughout the 

 transitional stages, but it never unites with the components of 

 the multiple as McClung found in Hesperotettix and Mermiria. 



In the spermatogonial metaphase cells the V first appears. 

 It is always on the periphery of the ring with the apex pointing 

 inward, while its rod mates may be anywhere on the periphery, 

 sometimes near it, sometimes opposite it. 



From the spermatogonia through the spermatocytes this 

 multiple can be traced. It divides longitudinally in spermato- 

 gonia. In the first spermatocyte the tetrads divide transversely 

 separating the V from its rod mates. Half of the second spermato- 

 cyte cells receive the V and half receive the rod mates of the V 

 (Figs. 37-47). In the second spermatocyte we have every reason 

 to believe that the V divides longitudinally, each of the two 

 spermatids resulting thus receiving a V while from the other 

 second spermatocyte two spermatids result which will contain 

 the rod mates of the V. 



This is what takes place in the one V-type of /. suhguttata. 

 The associated rods in No. 588 /. fiava (Figs. 5-8) are easily 

 distinguishable in the polar view of the spermatogonial metaphase 

 and their size 16 and I4 in the series corresponds to that of the 

 arms of the V in No. 503. Their behavior can not be traced as 



