Ferrv, Lancefield and Mefcz: Mutations in Drosophila 375 



Comparison. — Vermilion resembles 

 the character of the same name in 

 Drosophila inclanogastcr," D. z'irilis,'' 

 D. obscura.' and D. Iiydci.'' 



Abbreviated (ab). 

 Figure 15, No. 2 



Description. — In abbreviated, the 

 second, third, and fourth longitudinal 

 veins fail to reach the margin of the 

 wing, the second and the fourth being 

 affected the most. Usually the anterior 

 cross-vein is missing though this is not 

 a constant characteristic. Occasionally 

 one of the scutellar bristles is bent at 

 right angles to the scutellum. The 

 wing itself is more pointed and nar- 

 rower than the normal wing. 



Origin. — (R1453). Fixty-six males 

 were found in the first hybrid genera- 

 tion of a mating of rough scalloped by 

 blunt approximated. 



Broken (bk). 

 Figure 16, No. 7 



Description. — In broken, the second, 

 third, or fourth veins, or any combina- 

 tion of these, fail to meet the margin. 

 Pure stock has not yet been obtained, 

 hence it is not certain that the char- 

 acter always manifests itself. 



Origin. — (R1532). Seven yellow 

 scute rough stump broken females were 

 found in the second generation from a 

 mating of vermilion by yellow scute 

 rough stump. 



Crossveinless {c). 

 Figure 15, No. 3 



Description. — Crossveinless is char- 

 acterized by the absence of the pos- 

 terior cross-vein and usually of the 

 anterior cross-vein also. A small part 

 of the anterior cross-vein may be pres- 

 ent as far as the sense organ. The 

 fifth vein enlarges as it meets the mar- 

 gin of the wing like a delta. There is 

 also a slight enlargement of the other 

 longitudinal veins as they meet the 

 marginal vein. 



Origin.- — (R1627). Several males 

 were found in ragged stock. 



Comparison . — Crossveinless resem- 

 bles the crossveinless of D. virilis^^ and 



D. mclanogaster^ except for the apical 

 enlargement of the veins. The latter 

 feature is sometimes seen in our stock 

 of crossveinless in D. virilis, but not 

 commonly. 



Second Chromosome Characters 



Approximated (a). 

 Figure 17, No. 10, and Figure 21 



Description. — In approximated flies 

 the two cross- veins of the wings are 

 much closer together than in the wild- 

 type flies. The legs are also greatly 

 modified, the first tarsal joint of each 

 leg being absent and the remaining 

 ones shortened. 



Origin. — ( L88 ) . About twenty males 

 and females were found in a normal 

 mass culture. 



Comparison. — The wing modification 

 involved in this character is seen in 

 mutants of other species, but not, so 

 far as we know, in company with the 

 leg modifications found here. 



Spread (sp). 



Description. — In spread the wings 

 are held at an angle of almost ninety 

 degrees from the body and are curved 

 down. In older flies, the wing is usu- 

 ally curled or torn along the margin 

 and the tip is often gathered in. 



On^m.— (W18, W19). Two males 

 and one female were found in a mat- 

 ing for sparse. 



Comparison. — Spread resembles in a 

 general way the numerous spread wing 

 mutant characters of other species of 

 Drosophila, but so far as we know 

 none of the latter agrees with it in de- 

 tail. 



Blunt (b). 

 Figure 19 



Description. — The scutellum is square 

 instead of pointed in blunt. Usually 

 one or both of the anterior scutellar 

 bristles are missing, though all four 

 scutellar bristles may be present, in 

 which case the posterior ones are very 

 much closer to the anterior ones than 

 in the normal condition. 



Origin.— (W13, W17). Blunt was 

 found in the second generation of a 

 mating involving approximated. 



