680 C. E. McCLUNG 



the Stenobothrus type of chromosomes, (5) the movement of 

 the chromatids in the metaphase in these two types, (6) the rela- 

 tion of the chromosomes to the archoplasmic fibers in the two 

 types, (7) the form of the anaphase chromosomes in Hippiscus 

 and Stenobothrus types, (8) the results of the first spermatocyte 

 mitosis under the conditions of the two types, in terms of the 

 chromosomes, (9) the results of the second spermatocyte divisions 

 in the two types. 



Because of the involved and contradictory nature of the various 

 accounts it has seemed best to review briefly the work of the dif- 

 ferent authors, individually, according to the analysis proposed, 

 and then to consider the general evidence on each of the points. 

 By this means it will be possible to exclude the palpably incorrect 

 portions of the various descriptions and to present for judgment 

 those possibly correct ones upon which there is difference of opin- 

 ion. The papers on each family will be grouped together. 



a. Acrididae 



Wilcox ('95) in his paper upon the spermatogenesis of Melan- 

 oplus (Caloptenus) femur-rubrum describes the behavior of the 

 chromosomes in such a way that it is quite impossible to compare 

 his account in detail with more exact studies. The attempt to 

 do this will'nevertheless indicate somewhat the advance that has 

 been made since his work was done. (1) The 12 univalent 

 chromosomes of the spermatogonium become extended into a 

 granular thread upon which the chromatin collects at twenty- 

 four points, and then the thread breaks transversely into 12 

 dumb-bells. (2) By joining these dumb-bells in pairs, 6 tetrads 

 are produced, making 24 chromosomes. These are all in 

 the form of rings. (3) Contraction results in the production 

 of metaphase chromosomes having also an annular shape. (4) 

 The rings are placed on the spindle parallel to its axis. (5) By 

 the first spermatocyte mitosis they are separated into half rings. 

 (6) No clear statement of fiber attachment is given. (7) Chro- 

 mosomes in the anaphase are not described. (8) The first 

 spermatocyte mitosis is a reduction division. (9) Also the 

 second spermatocyte division is reductional. 



