50 STUDIES IN SPERMATOGENESIS. 



spread out in the nuclear space, and, with the exception of the hete- 

 rochromosomes, unite to form a continuous spireme. 



(5) In several of the species of Coleoptera and in Aphrophora, it 

 has been shown that a body staining like chromatin develops in the 

 spermatids, increasing in size for a time, then breaking up into gran- 

 ules and disappearing. This body evidently has no relation to the 

 heterochromosomes, as it is the same for all of the spermatids. Its 

 staining qualities suggest that it may be material derived from the 

 chromosomes. It is finally dissolved in the karyolymph. 



(6) In iron-haematoxylin preparations the heterochromosomes of the 

 Coleoptera vary greatly in their staining properties during mitosis. In 

 some species they stain exactly like the ordinary chromosomes, in 

 others the larger one of the unequal pair holds the stain more tena- 

 ciously than the others and also than its smaller mate, and this is true 

 in several cases where the heterochromosome is smaller than the other 

 chromosomes, which destain more readily. The odd chromosome 

 of the Elaters stains less deeply than the others in the first spermato- 

 cyte. In the growth stage they stain more deeply, as a rule, than the 

 spireme, with iron-hsematoxylin or thionin, stain red with safranin- 

 gentian and green with Auerbach's methyl green-fuchsin combination. 



(7) Aphrophora quadrangularis agrees with the Anasa group of 

 Hemiptera heteroptera in having a pair of w-chromosomes and an odd 

 chromosome in the spermatocytes, but differs from many of that group 

 in that the odd chromosome divides in the second mitosis instead of 

 the first. It also differs from other known forms in exhibiting hete- 

 rochromosomes in certain stages of the oocytes. 



(8) The two species of Lepidoptera examined have an equal pair 

 -of heterochromosomes. 



