Description of Characters. 19 



veins, and sometimes of the third, are delta-like (fig. 9, plate 2) ; the posterior cross- 

 vein is sometimes broken, and occasionally the entire wing is soft in texture. 



The origin and behavior of cut are such that we are unable to tell, as yet, whether 

 the character is an allelomorph of short or is due to a dominant modifier closely 

 linked to short. The character itself seems to be of the opposite nature from that of 

 short, increasing instead of diminishing the size of the veins, which argues somewhat 

 against its being an allelomorph. On the other hand, it should be noted that in 

 females heterozygous for cut the same vein (fifth) is affected as is affected by short. 

 The absence of cross-overs between the two genes (thus far) indicates that if not 

 allelomorphic they must be very closely linked. 



Origin. — (M 102.) From a mating (M 40) of a female heterozygous for short and 

 vermilion, by 2 short garnet brothers, approximately 200 offspring of the expected 

 classes were obtained, and in addition one female with the wings slightly spread and 

 the end of each fifth vein thickened. This female proved to be heterozygous for cut. 

 Her daughters were all normal, but her sons were of two classes, approximately half 

 (19) short and half (16) cut. The data in this case show that the mother of this 

 exceptional female was not heterozygous for cut, else cut sons and additional hete- 

 rozygous daughters should have appeared. The mutation evidently occurred in one 

 of the parents or in the egg that gave rise to this female. 



Comparison. — Cut shows a slight resemblance to "bifid" in D. melanogaster (Mor- 

 gan and Bridges, 1916, p. 29), but not enough to make homology probable. 



Rugose (r). 



Description. — This character derives its name from the roughening of the eye 

 due to disarrangement of the ommatidia (fig. 4, Metz, 1918). The color of the eye 

 is also affected, being considerably lighter than normal and having a more yellowish 

 tinge. The eye is full-sized, however, and the ommatidia are not coalescent, as 

 they tend to be in the two following characters glazed and wax. Rugose is sex- 

 limited, appearing only in the males. Its viability is excellent. 



Origin. — (V611.) One male from a pair mating of a confluent male by normal 

 female (Metz, 1918, p. 110). 



Glazed (r«). 



Description. — Glazed is a more extreme eye modification than its allelomorph 

 rugose. The ommatidia show greater disarrangement, many are lacking, leaving 

 smooth spaces on the eye-surface, and others tend to coalesce. The whole eye has a 

 glazed or varnished appearance, but lacks the lighter color shown by rugose. It 

 appears in both sexes. Glazed females are usually sterile and the males have poor 

 viabihty, making the character less useful than rugose. 



Origin. — Glazed appeared slightly before, and independently of, rugose. One male 

 was found in a mass culture (see Metz, 19l6d, p. 599). 



Comparison. — (See under wax, below.) 



Wax (r"). 



Description.— Wax flies resemble glazed, but the eyes are more extremely affected. 

 They are of a pale yellowish, uneven color, and the ommatidia are fused together, 

 or absent, so that the surface of the eye has a waxy appearance. The eyes are con- 

 siderably reduced in size and are narrowed, leaving a white zone much broader than 

 usual around the margin. In the eye itself on the posterior side there is often a 

 white or cream-colored patch resembling a vesicle. Wax, like glazed, appears in 

 both sexes and has sterile females. 



Origin.— {Y 1095.) Three males were found in a stock bottle carrying fused. 



Comparison.— In appearance wax and glazed both resemble the sex-linked char- 

 acter "lozenge" in D. melanogaster. The eye of lozenge more nearly approaches 



