1910.] NATURAL SCIENCES OF PHILADELPHIA. 309 



that they may have some functional significance seems probable and 

 this will be discussed under the development of the spermatid. 



Telea polyphemus. 



Telea polyphemus, which belongs to the sub-family Saturinae, is 

 found in its larval stage feeding upon oak and other shade trees. After 

 the cocoon is made, in part from the folded leaves of its food plant, 

 it falls to the ground. Material was collected from about Bellefonte, 

 Pa., and from Newark, N. J., through the kindness of Mr. Herman H. 

 Brehme. Development in T. polyphemus is somewhat more rapid 

 than in promethea, and shows a greater dependence upon temperature 

 conditions. 



Spermatogonia which are found in the periphery of the testes show 

 always an eccentrically placed mass formed by a plasmosome in which 

 is embedded a number of darkly staining granules (fig. 62). The 

 last spermatogonial division is preceded by the formation of a thick 

 spireme wmich segments into a large number of chromosomes, probably 

 sixty, though the number is so great and the chromosomes so massed 

 that it is impossible to be sure that this count is correct (Pi. XXIV, fig. 

 66) . A side view of the spindle shows the dumbbell-shaped chromosomes 

 arranged upon the spindle fibres (fig. 67) ; these divide "symmetric ally 

 and are seen in telophase as feathery chromosomes arranged upon 

 linin threads (fig. 69). It is possible that a synapsis takes place at 

 this time, but, owing to the large number of chromosomes, I have been 

 unable to observe it. The chromatin now forms a long slender spireme 

 which in both smears and sections is seen to be made up of granules 

 (fig. 70). This spireme gradually becomes looped (fig. 71) until 

 concentration is complete and all the chromatin lies in a darkly stained 

 mass against one side of the nucleus (fig. 73); the chromatin then 

 passes out of this contraction stage by a loosening of the loops (figs. 

 74 and 75), which stretch out into the nucleus and in late post-synapsis 

 completely fill it (fig. 76). The spireme is made up of a number of 

 threads which seem to be composed of single granules, though the 

 linin threads are double, and in a few cases (smear preparations) 

 there was some evidence in these granules of a longitudinal split. At 

 this stage (fig. 75) a large deeply staining body appears for the first 

 time and becomes more pronounced as the basi-chromatin loses its 

 staining reactions, and throughout the growth stage of the sperma- 

 tocyte this body retains its staining reaction and may be seen either 

 as a single or dumbbell-shaped structure. The chromatin now resumes 

 its staining property and the chromosomes appear as broken segments 

 of the spireme usually bent or twisted at their center; then these 



