ORTHOPTERAN SPERMATOGENESIS 661 



planeta there were 33. Blatta has also been studied by Stevens 

 ('05) and Wassiheff ('07) with the same numerical results. 

 Farmer and Moore ('05) report 32 chromosomes for Periplaneta 

 plus a conspicuous nucleolus which the authors believe is lost 

 during each mitosis. The work of the other students of the 

 Blattidae makes it certain however that the English investi- 

 gators incorrectly interpreted the behavior of the accessory 

 chromosome which is characteristically Orthopteran in this 

 family. 



6. Forficulidae. The Forficulidae, taxonomically, are not now 

 regarded as a family of the Orthoptera and their germ cells show 

 a characteristic difference in the nature of the accessory chromo- 

 some. According to Randolph ('08) in Anisolabis; and Stevens, 

 de Sinety, Zweiger, and possibly St. George, in Forficula, there is 

 an even number of chromosomes, 24, in the spermatogonia. Of 

 these, according to Stevens, one pair constitutes an unequal 

 tetrad in the first spermatocyte and has all the characters of an 

 idiochromosome pair of the Hemiptera and Coleoptera. 



d. Summary of results on spermatogonia of Orthoptera 



From the foregoing statements I believe the following conclu- 

 sions are justified: (1) The diploid number of chromosomes in 

 the Orthopteran male is uneven; (2) The diploid complex in 

 each case may be resolved into a duplicate series characterized 

 by differences in relative size; (3) an odd element, sometimes 

 distinguishable by excessive size, may not thus be grouped with 

 a mate and is further marked by occasional peculiarities of behav- 

 ior; (4) the typical form of the spermatogonia! chromosome is a 

 rod which takes a radial position in the equatorial plate of the 

 metaphase with the fiber attached at the inner end; (5) in divi- 

 sion the longitudinal halves of the chromosome separate in the 

 plane of the equatorial plate, beginning at the inner end, and 

 pass to the pole as straight rods; (6) an exception to (4) and (5) 

 is furnished by certain chromosomes of Stenobothrus, Chorthip- 

 pus, Chloealtis and Trimerotropis which are J- or V-shaped with 

 the fiber attachment at the bend. 



