CHROMOSOMES IN COREII) HEMIPTEKA. 83 



nece-- arily -onieNvhat meagre, but they are perfectly clear as far 

 as they go. 



III. DESCRIPTIVE. 



A. Oo gene sis. 



Tin- n -uli- on 'i^i.-nesis are confined to the chromosomes of 

 tin- oo-i.nial and o.">cyte divisions. No attempt ha- been made 

 lot race tin- full history of the growth period, but an * xamiiuit it >n 

 ct a leu eggs tak-n from the ovarian tubes seems to show that 

 no definite < hioinat in-nucleolus or persistent oogonial chromatin 

 eleineiit i- pre-em . as stated by Wilson ('06). The nucleus at 

 tin- time contains main- faintly staining chromat in threads and 

 -e\t ral -mall nuclei di whose nature was not determined. Foot 

 ami "Mr.il.ell ia\e found the same condition to In- true in 



l:nsthisti(^, a pi -iiiatomid. 4 



i. Archimcrus alternatiis. 



The spermatogonial groups 1 have been figured by \\iUon in 

 the -t i ..ml ..I his "Studies ' ('056), but for the sake of comparison 

 i\\o more are -hown (Fig. i, c and d). Each group has 15 < hn>- 

 mosomes, tu.> <>i uhich, the m-chromosomes (following \\il-on'- 

 tei niino|oL;\ . <an aluays be identified by their very small -i/e. 

 < )| the icniainiir^ ihirtei-n no one ran be positive!) ideiilitied, by 



its size or shape, as the idiochromosome. In tlu- spermatocyte 



di\i-ion- thi- t In > Milosome passes undivided t<> our pole ol the- 

 ^pindle in the 'tr*t mitosis and divides equally in the -econd 

 \\il-..n, '05 I 'hi* condition is peculiar to Archimcrus alone 



.| all the (".'ivid.i- >o far described, 6 but a reexamination of the 

 >prrmaiiic\ ie stages in new material shows beyond doubt that 

 \\il-.. n'- account i> correct. The idiochromosome can be easily 

 identified in the- first mitosis by its peripheral position on the 

 >pindle ami by it- inn t mstricted contour when the other chromo- 

 somes are in eail\, and even late, anaphase. It passes to one 

 pole o|" ihe -pindle a little behind the others. Further, in the 



St. \, i ! In t.n .chromosomes" in certain stages of the growth 



I of the -n homopteran. 



. i.,,,ni(.ii- j. .it li..it. .in ..t page 80. 



l'i,. i, 3801 \\il-t.n li.i- .iN.. i..iind a similar condition in Pachylis gigas (unpub- 

 lishi 



