ORTHOPTERAN SPERMATOGENESIS 689 



h. Locustidae 



Stevens ('05), in connection with a series of studies upon the 

 accessory chromosome, describes briefly the spennatogenesis of 

 Stenopelmatus, a Locustid. Several errors appeared in this 

 paper which were later corrected. Such of her final conclusions 

 as relate to this study are indicated in the following: (1) From 

 the 47 chromosomes of the spermatogonium there are formed by 

 telosynapsis in the prophase of the first spermatocyte twenty- 

 three tetrads and an unpaired accessory chromosome. (2) The 

 tetrads thus produced have the form of rings, crosses and rods. 



(3) In the metaphase the same series of forms may be traced. 



(4) The chromosomes are so placed in the spindle that their plane 

 of longitudinal cleavage lies in the equatorial plate. This is 

 clearly indicated by persisting linin connections. (5) By move- 

 ment of the chromatids along the plane of the longitudinal split 

 in the late metaphase, the chromosomes have the form of rods 

 extended in the direction of the spindle axis. (6) Fiber attach- 

 ment is not described, but by inference it must be at the synaptic 

 points. (7) Anaphase chromosomes are in the form of simple V's 

 or double rods. (8) An equation division occurs in the first sper- 

 matocyte. (9) Segregation of homologous chromosomes results 

 from the second spermatocyte mitosis. 



Otte ('07) has confined himself to a study of the Locustid, 

 Locusta viridissima, and comes to some unique conclusions regard- 

 ing maturation phenomena. His results may be summarized as 

 follows: (1) There is a constant series of chromosomes recog- 

 nizable by differences of size. The paired elements of the sperma- 

 togonium, after becoming elongated in the first spermatocyte 

 prophase, join together side by side to form the haploid number — 

 parasynapsis. (2) Of these, the longer elements become rings 

 by a bending of the double thread until the ends meet, at which 

 point they may, or may not, fuse. These annular chromosomes 

 may continue in this form or they may become compressed so 

 that they break at the point of greatest curvature — opposite 

 the free ends of the loop — and thus produce parallel rods, each of 

 which shows a space representing that produced by the earlier ap- 



