Germ-Colls in Chrvsomelid Beetles. 247 



tendency to stain more intensely. ''Dafiir spricht erstens die friihe 

 Absonderung der Geschlechtszellen, schon zu einer Zeit, wo das 

 Meso- und Entoderm nicht scliarf getrennt ist, nnd ferner die sebr 

 grosse Aolmlielikeit bei den Zellelementen in den ersten Stadien ihrer 

 Entstebnng." 



According to Carriere and Burger (1897) tbe primitive germ- 

 cells of Ch-allcodoma muraria were probably derived from cells of 

 tbe mesodermal layer shortly after its appearance. A few cells in 

 the dorsal wall of the somites of the third, fourth and fifth abdominal 

 segments on either side of the body proliferated to form egg-shaped 

 bodies. In further growth these germ-cells decreased in size as 

 a result of multiplication. Later, they wandered from the third 

 and fourth segments into the fifrh, where they lay behind one another 

 in their original succession. 



In an endeavor to test the ^'Dzierzon theory," that the eggs which 

 produce drone bees are normally unfertilized, Petrunkewitsch (1901- 

 03) discovered some unusual maturation divisions. In "drone eggs" 

 the first polar body passed through an equatorial division, each of 

 its daughter nuclei containing one-half of the somatic number of 

 chromosomes. The inner one of these daughter nuclei fused with the 

 second polar body, which also contained one-half of the somatic 

 number of chromosomes ; the resultant nucleus with sixteen chromo- 

 somes, the "Richtungscopulationskern" passed through three divisions 

 giving rise to eight "doppelkernige Zellen." After the blastoderm 

 was completed, the products of these eight cells were found in the 

 middle line near the dorsal surface of the egg, where the forma- 

 tion of the amnion had already begun ; the nuclei of these cells 

 were small, and lay embedded in dark staining cytoplasm. Later 

 they were found just beneath the dorsal surface near the point of 

 union of the amnion with the head-fold of the embryonic rudiment. 

 They were next discovered Ix^tween the epithelium of the mid- 

 intestine and the ectoderm ; from here they migrated into the coelomic 

 cavities, and finally, at the time of hatching, formed a "welleii- 

 artigen" strand, the germ-gland, extending through the third, fourth, 

 fifth and sixth abdominal segments. The fertilized eggs of the bee 

 were also examined by Petrunkewitsch, but no "Richtungsoopula- 



