Further Studies on the Chromosomes lOQ 



CICINDELA VULGARIS (fAM. CICINDELID^) 



In Cicindela primeriana ('06, PL XIII, Figs. 198 to 206) the 

 number of chromosomes was twenty, and the heterochromosome 

 pair a large trilobed bivalent. In Cicindela vulgaris the number 

 is twenty-two, three larger than the others (Fig. 87). In the first 

 spermatocyte spindle the conspicuous elements are the trilobed 

 heterochromosome group and a four-lobed or cross-shaped macro- 

 chromosome (Fig. 88). The divisions are like those of Cicindela 

 primeriana. 



OTHER CHRYSOMELIDt^ 



Among the Chrysomelidae, several other cases of an unequal 

 pair of heterochromosomes will be briefly referred to. Lema 

 trilineata (Figs. 89 to 92) has thirty-two chromosomes, one very 

 small. The synizesis stage is of the loop type followed by synapsis. 

 Doryphora clivicolis is quite similar to Doryphoria lo-lineata 

 ('06, PI. XII, Figs. 151 to 186), and the character of the hetero- 

 chromosome group is much more easily determined. The reduced 

 number of chromosomes is seventeen, instead of eighteen as in 

 lo-lineata. The chromosomes of the first and second maturation 

 divisions are shown in Figs. 93 to 96. 



Chrysochus auratus has the loop type of synizesis and synapsis 

 and a typical pair of quite unequal heterochromosomes (Figs. 

 97 and 98), The reduced number is thirteen. Haltica chalybea, 

 the steel-blue flea-beetle, has twenty-two chromosomes in the 

 spermatogonium (Fig. 100). Only occasionally a specimen of 

 this species has been found in the net, and these have been studied 

 with the aid of aceto-carmine. No drawings have been made of 

 synizesis, synapsis or growth stages. Fig. loi is a prophase 

 showing the heterochromosomes {hi and h.^ and another con- 

 densed pair of chromatin elements which may be m-chromosomes. 

 In the later prophase when the chromosomes are coming into the 

 spindle, the heterochromosomes are often widely separated (Fig. 

 102), and the same is true of the metaphase (Figs. 103 to 105), so 

 that twelve chromosomes show in the equatorial plate of the first 

 spermatocyte (Fig. 106), but in the late anaphase (Fig. 107), the 



