ORTHOPTERAN SPERMATOGENESIS 659 



It would seem very evident therefore that in the spermatogonia 

 of the Acrididae we are deahng with a chromosome complex 

 of a very definite and precise organization which, in the great 

 majority of cases, presents itself without essential variation in 

 number, size and form, fiber attachment, arrangement in the 

 metaphase and behavior during division of its elements. Steno- 

 bothrus and Pamphagus seem to be definite exceptions in some 

 of these respects, but doubtless were we more familiar with all 

 the facts in the case a larger harmony would become manifest. 



2. Locustidae. I desire to consider with much detail only the 

 conditions in the Acrididae, but since exceptions to the general 

 behavior of the chromosomes in the Orthoptera have been taken 

 from studies on other families I shall be obliged to give them 

 consideration. This I shall do as briefly as possible, going into 

 details only when it is necessary. 



My own work began on the Locustidae and I made a com- 

 parative study of Xiphidium, Anabrus, Orchesticus, Scudderia, 

 Conocephalus and some others which I did not identify. So 

 far as I was able to go at the time there seemed to be a uniformity 

 here also, but of a somewhat different order. Instead of 23 

 chromosomes there appeared 33 and the accessory chromosome 

 was very large and conspicuous. The chromosomes were rod- 

 shaped, arranged radially in the metaphase with terminal fiber 

 attachments, and they divided regularly into two equivalent 

 straight rods by a cleft extending from the center outward in 

 the plane of the equatorial plate — all except one chromosome 

 in Anabrus which at the time I could not explain, but later recog- 

 nized as a multiple. None of my students have worked on this 

 family but other investigators have, and the result has been less 

 uniformity in chromosome numbers than in the Acrididae but in 

 other respects no essential differences. Thus Stevens ('05) 

 reported 46 chromosomes in Stenopelmatus, but later recognized 

 this as an error and gave the correct count as 47. In Ceuthophilus 

 ('12) she found 37 chromosomes but in both cases no exceptional 

 behavior. Davis ('08) and Meek ('12 a) in Steiroxys agree on 

 29 as the number present with no atypical behavior. De Sinety 

 ('01) studied Decticus, Platycleis and Orphania but gives the 



