354 W. E. HOY, JR. 



somes varies in the bee, the number is always eight or a multiple 

 of this. This agrees with Petrunkewitsch's theory that the 

 64 chromosomes, which he found in cells of the blastoderm of 

 fertilized eggs, were due to a splitting up of quadrivalent chromo- 

 somes. A similar fragmentation appears to be characteristic of 

 parthenogenetic individuals, i. e., the drones. This is also the 

 case in other Hymenoptera, as Armbruster reported in Osmia, 

 and Granata in Xylocopa. 1 



In Nematus Doncaster suggests that perhaps the chromosomes 

 of the germ cells "may be compound and consist of a number of 

 smaller units which become separated in somatic cells" (p. 107). 



The case of Phragmatobia is interesting since in this form 

 Seiler has demonstrated a dimorphism of the eggs with respect 

 to their chromosome content. The female diploid complex is 

 composed of an x, 2 y's, and 54 autosomes. The counts made 

 in the blastoderm of developing eggs can be analyzed as follows: 

 The 58 complex is due to a splitting in two of the large y-chromo- 

 some, and is from a female. The complex with 6 1 chromosomes 

 is also from a female in which the x-chromosome has split up into 

 four segments and the large y-chromosome has also split up into 

 two parts. The complex with 62 chromosomes is from a male 

 where the two ^-chromosomes have each split up into four seg- 

 ments. "This striking explanation has absolutely nothing im- 

 probable about it, since a splitting of the sex chromosomes in the 

 somatic nuclei has been observed quite often" (trans). 



In Gryllus domesticus Gutherz found that the accessory chro- 

 mosome is absent in the cells of the soma. This can be explained, 

 he says, only by assuming a "Diminutionsprozess" or by assum- 

 ing that since the accessory chromosome does not participate in 

 the early stages of development, it does not make its appearance 

 until later. Either of these explanations, he thinks, places the 

 theory of the individuality of the chromosomes in an extremely 

 delicate position. 



Robertson considers that the cells in Acridium containing 26 

 chromosomes are double cells with double sets of cell organs. 

 These may have been produced by the fusion of two cells or 

 by the suppression of cell division after nuclear division had 

 taken place. 



1 Fide Buchner (Referate), Arch. f. Zellf., Bd. 5, H. 3 (1910). 



