3IO EDMUND B. WILSON. 



the new material of calva differs from the Long Island material 

 that I formerly described in the absence of tlie small impaired or 

 heterotropic chromosome, though in every other detail they are 

 identical. To facilitate the comparison I give three new figures 

 from the Long Island material (which, as above stated, includes 

 only two slides from the Paulmier collection). The first division 

 here always shows 15 chromosomes (Fig. 2, a] of which two, 

 the unpaired chromosome and the small idiochromosome, are 

 much smaller than the others. Owing to the passage of the 

 unpaired chromosome to one pole without division in the first 

 maturation division the secondary spermatocytes are of two 

 types, showing respectively 14 and 13 chromosomes (Figs. 2, b, 

 2, r)--a relation shown with perfect clearness in a large number 

 of cells. In all my new material on the other hand (from New 

 York, Ohio, Colorado and New Mexico) the chromosome groups 

 are exactly similar to those of the Long Island form except that 

 the small unpaired chromosome is missing. The first division 

 accordingly always shows 14 chromosomes instead of 15, of 

 which one (the small idiochromosome) is smaller than the others 

 (Fig. 2, d}. The second division always shows 13 chromosomes, 

 (Fig. 2, /) of which one is a typical idiochromosome-bivalent ; 

 and in the ensuing division all the spermatids receive i 3 chromo- 

 somes, half receiving the small idiochromosome and half the 

 large. Both the spermatogonial and the ovarian groups accord- 

 ingly show 26 chromosomes, the small idiochromosome being 

 present in the male only (Fig. 2, /). In every respect, there- 

 fore, these individuals show the typical pentatomid relations, 

 and agree with Type B of Metapodhts. 



Banasa dhnidiata agrees essentially with this except that to 

 my astonishment the number of chromosomes was found to be 

 much smaller, namely, in the spermatogonia 16 (Fig. 2,/), in the 

 first division nine (Fig. 2,g\ and in the second eight (Fig. 2, //). 

 It is noteworthy that these two species, which are so closely 

 similar as sometimes to have been confused by systematists, should 

 differ so widely in the number of chromosomes. 



The difference between the material from Long Island, labeled 

 "Banasa catva," and my own at first led of course to the sus- 

 picion that an erroneous identification was at fault ; and this is 



