CONTENTS. 



Page 



I. Introductory 5 



General Introduction 5 



Chromosome relationships 8 



Chromosomes of Drosophila 



virilis 9 



Previous work on Drosophila 



virilis 10 



Present aim of the work 10 



Description of Drosophila virilis 10 



Source of material 11 



Methods employed 12 



Acknowledgments 13 



II. Linkage Group I. Sex-linked 



Characters 14 



Description, origin, and com- 

 parison of sex-linked charac- 

 ters 14 



Sepia 14 



Yellow 15 



Fraj'ed 15 



Crossveinless 15 



Vermilion 15 



Vesiculated 15 



Oblique 16 



Singed 17 



Hairy 17 



Magenta 17 



Forked 17 



Triangle 18 



Short 18 



Cut 18 



Rugose 19 



Glazed 19 



Wax 19 



Droop 20 



Linkage in Group I, and con, 

 struction of X-chromosome 



map 21 



Sepia 22 



Yellow 22 



Frayed 22 



Crossveinless 22 



Vermilion 22 



Vesiculated 23 



Singed 23 



Oblique 23 



Hairy 24 



Magenta and forked 24 



Triangle and short 24 



Cut 25 



Rugose, glazed and wax 26 



Droop 26 



III. Linkage Group II 32 



De.scription, origin, and com- 

 parison of characters in 



Group II 32 



Confluent 32 



Concave 32 



Double 32 



Broken 33 



Page 



III. Linkage Group II— Continued. 



Linkage data 34 



Detection of linkage in 



Group II 34 



Confluent and concave 34 



Double with concave and 



confluent 34 



Confluent and broken 34 



Cross-over values in Group 



,11 .34 



Confluent and concave 34 



Confluent and double 34 



Confluent and broken 35 



Construction of second-chromo- 

 some map 35 



IV. Linkage Group III 35 



Description, origin, and compar- 

 ison of characters in Group 



III 37 



Scaly 37 



Spread 37 



Hunch 3S 



Telescoped 38 



Garnet 39 



Linkage data 39 



Detection of linkage in Group 



III 39 



Scaly and telescoped 39 



Steel and telscoped 39 



Hunch and telescoped 39 



Scaly, hunch, and telescoped 39 



Scaly and garnet 40 



Hunch, telescoped, and 



spread 40 



Cross-over values in Group 



HI 40 



Scaly and htmch 40 



Scaly and telescoped 40 



Scaly and spread 40 



Scaly, hunch, and telescoped 40 

 Scaly, hunch, telescoped, 



and garnet 41 



Spread and garnet 41 



Construction of third-chromo- 

 some map 41 



V. Linkage Group IV 43 



Description and origin of char- 

 acters in Group IV 43 



Acute 43 



Pinched 44 



Hump 44 



Linkage data 44 



Detection of linkage in Group 



IV 44 



Acute and pinched 44 



Acute and iiump 44 



Pinched and hump 45 



Complete linkagr of acute, 



pinched, and hump 45 



1 1 7'1 :>7 



