218 THE AMERICAN NATURALIST [Yol. LYI 



Tiny it) 



Description. — Tiny-bristle flies usually have small an- 

 terior dorso-central bristles. Sometimes the two anterior 

 scutellar bristles ara also small. Occasionally all the 

 bristles may be small, so that the individual may be in- 

 distinguishable from a true " small-bristle " fly. The 

 character is rather variable and, in many cases, is very 

 hard to separate from normal. This difficulty was so 

 great that the stock was finally discarded. 



Origin. — A single male was found on the last count of 

 the offspring from a pair mating. It is possible that 

 other tiny males were present among the previous off- 

 spring and escaped observation since the character is 

 very inconspicuous. 



Square (sq) 



Description. — The wings are about two thirds the nor- 

 mal length with the ends almost square instead of pointed 

 (Fig. 11). A characteristic slight wave extends through- 

 out the length of the wing. The females are sterile and 

 the viability of the males is rather poor. 



The description of square suggests that of rudimentary 

 melanog aster but square is much less extreme than rudi- 

 mentary; the wing is not shortened so much and is not 

 cut off so squarely. 



Origin. — Among the offspring from a pair mating 

 (rough female by orange rough stump male) several 

 square males were found, indicating that the mother was 

 probably heterozygous for square. 



Reduced {re) 



Description. — Eedueed flies regularly lack the two an- 

 terior dorso-central bristles; occasionally, they also lack 

 one of the posterior dorso-centrals; and less frequently, 

 all four are absent. In combination with scute-2, how- 

 ever, the more extreme condition of reduced is frequently 

 found (Fig. 7). The reduced gene also affects the shape 



