Further Studies 0J7 the Chromosomes 105 



were found. It will therefore be necessary to obtain the larvae 

 or pupae before the maturation stages can be studied. 



LIMONEUS GRISEUS (fAM. ELATERID^) 



In previous work an odd chromosome was found in two species 

 of Elateridae ('06). In both, the male number of chromosomes was 

 nineteen, and in one the female number (twenty) was determined 

 ('06, PL XIII, Fig. 229). In both species the unpaired chromo- 

 some was the smallest one. 



In Limoneus griseus there are seventeen chromosomes in the sper- 

 matogonia (Fig. 34), and the heterochromosome {x) is the largest. 

 The synapsis and synizesis stages are similar to those of Photinus 

 pennsylvanicus. The most conspicuous stage in the transition 

 from spermatogonia to spermatocytes is one in which the condensed 

 chromosomes appear as approximately spherical bodies which 

 nearly fill the small nucleus (Fig. 35). In Fig. 36 the chromosomes 

 are united and somewhat elongated. Elongation continues until 

 all traces of the individual chromosomes, with the exception of the 

 odd chromosome (x), are lost in the fine, closely wound spireme 

 with which the heterochromosome remains connected by linin 

 threads (Fig. 37). As the nucleus enlarges, and the spireme 

 becomes thicker and less stainable, the heterochromosome shows 

 a central vacuole (Fig. 38), and a little later it appears like a 

 spireme wound about in plasmosome material and still connected 

 with the much paler general spireme (Fig. 39). At this point it 

 resembles in its behavior the "accessory" of Orchesticus and 

 Xiphidium (McClung '02, PI. VII, Figs. 4, 5, 12). In the later 

 pale spireme stage (Fig. 40) the heterochromosome is again con- 

 densed. 



In the first spermatocyte spindle the odd chromosome appears 

 in the equatorial plate in metaphase (Figs. 41 and 42), does not 

 divide, but lags behind the daughter plates (Fig. 43). The chro- 

 mosomes of a pair of daughter plates are shown in Fig. 44, In 

 the telophase (Fig. 45) the heterochromosome holds the haema- 

 toxylin after the other chromatin has been almost entirely de- 

 stained. In the second spermatocytes (Fig. 46) the unpaired 



