68 Comparison of Characters. 



melanog aster, as for example, dachsous and are, but each of the 

 latter involves additional modifications. The same is true with 

 respect to approximated in willistoni, which has short legs hke 

 dachsous. The second character is broken. This resembles cross- 

 veinless, or characters of this type of which there are several in other 

 species. One such autosomal character is known in obscura, two or 

 three are known in willistoni (one being sex-linked), and a sex-hnked 

 crossveinless is known in melanogaster and virilis. 



