180 CHARLES W. METZ AND JOSE F. NONIDEZ 
5. Then the double chromosomes reappear, apparently in the 
same form and relative position as before, and condense into 
bivalent prochromosome-like bodies (stage b) . 
6. The ordinary leptotene condition seems to be omitted 
entirely. 
7. The bivalent bodies of stage b elongate into diplotene 
threads that remain relatively condensed and clearly separate 
throughout the entire growth period, giving rise to the bivalent 
prophase chromosomes. 
8. In another species, A. notatus, the process appears to be 
essentially the same, but is somewhat confused by a spinning 
out and intertwining of the threads in the stage following stage b. 
9. The usual synaptic process is entirely wanting. Synapsis 
is effected in telophase at the beginning of the growth period by 
an intimate association of chromosomes that were already paired 
in anaphase. 
10. Superficially the early growth stages are not unlike those 
in the Hemiptera and other forms, but the chromatic structures 
are bivalent instead of univalent, 
11. Tetrad structures are not visible. 
12. The first division appears to be reductional for all of the 
chromosomes. 
LITERATURE CITED 
Arnold, G. A. 1908 The nucleolus and microchromosomes in the spermato- 
genesis of Hydrophilus piceus. Arch. f. Zellfor., Bd. 2, No. 1. 
Blackman, M. W. 1903 The spermatogenesis of the myriapods II. Biol. Bull., 
vol. 4; pp. 187-218. 
1910 The spermatogenesis of the myriapods VI. Biol. Bull., vol. 19; 
pp. 138-160. 
Davis, H. S. 1908 Spermatogenesis in Acrididae and Locustidae. Bull. AIus. 
Comp. Zool. Harvard, vol. 52, no. 2. 
Downing, E. R. 1905 The spermatogenesis of Hydra. Zool. Jahrb., Bd. 21; 
s. 379. 
Goldsmith, W. M. 1919 A comparative study of the chromosomes of the tiger 
beetles. Jour. Morph, vol. 32, pp. 437-488. 
KoRNHAUSER, S. I. 1914 A comparative study of the chromosomes in the 
spermatogenesis of Enchenopa binotata, etc. Arch. f. Zellf., Bd. 12, 
s. 241-298. 
LoMEN, Franz 1914 Der Hoden von Culex pipiens L. Zeits. Naturwiss., B. 52. 
