1913] Observations, o?i Chcetotaxy of Calliphorinae. 263 



9—3, 3, ac, 3, from scow, Boston, Aug. 8, gave 12 0^0^—3, 3, 3, 3. 



15 9 9—3, 3, 3, 3. 

 9 — 3, ac, 2, 3, from Bussey Institution, July, gave: 



18 cfcf— 3, 3, 3, 3. 8 9 9—3,3,3,3. 



9 — 3,' 2, 3, 3, from scow, Boston, Aug. 8, gave: 



10 d'cf— 3, 3, 3, 3. 14 9 9—3,3,3,3. 



1 cf —3, 3, 2, 3. Id' —3, ac, 3, 3. 



1 9 — 3, ac, ac, 3. 

 9—3, 2, 1, 3, from scow, Boston, Aug. 8, gave 10 d'c?'— 3, 3, 3, 3. 12 9 9 — 

 3, 3, 3, 3. This family was continued into the third generation and 

 will be considered below. 

 9 — 3, ac, 3, 3, from scow, Boston, Aug. 8, gave: 



7 cfcf— 3, 3, 3, 3. 7 9 9—3,3,3,3. 



19 — 3, 3, a / be, 3. 



Taking the totals of these families of females deficient in 

 bristles we find normal cf 6^102, normal 9 9 86, variants by 

 reduction 10 cf cf and 4 9 9, variants by addition, 1 9 . Thus 

 from^these rather small numbers we see the variants by re- 

 duction are 7%, while the variants by addition are 0.5%. 



I Let us consider now the progeny of females abnormal by 

 addition of bristles. 



9 — / abc, 3, 3, ! abc, from scow, Boston, Oct. 17, gave: 



30 o^cf— 3, 3, 3, 3. 219 9—3,3,3,3. 



1 d' —3, (a), 3, 3, (a), 3. 

 9 — 3, 3, 3, ab ! c, from scow, Boston, Oct. 17, gave: 



9 cfcf— 3, 3, 3, 3. 20 9 9—3,3,3,3. 



1 & —3, 3, 3, (a), 3. . 1 cf —3, ac, 3, 3. 



1 9 — 3, ac, ac, 3. 

 9 — 3, 3, a / be, .' abc, from scow, Boston, Aug. 8, gave: • 



40 cfcf— 3, 3, 3, 3. 32 9 9—3,3,3,3. 



3 &&—Z a ! be, 3, 3. 1 cf— 3, 3, a ! be, 3. 



1 cf— 3, (a), 3, 3, 3. 1 d' —3, ac, ac, 3. 



19 — 3, 3, a .' b .' c, 3. 2 9 9—3, a ! be, 3, 3. 



1 9 —3, 3, ac, 3. 1 9 —3, ab, 3, 3. 



1 9 —3, 3, 2, 3. 19 —3, ac, 3, 3. 



9 — a / be, a .' be, 3, 3, from scow, Boston, Aug. 8, gave: 



75 c^c^— 3, 3, 3, 3. 52 9 9—3,3,3,3. 



1 c^ —3, 3, a .' be, 3. 1 cf — 3 (a), 3, 3, 3. 



1 o" —3, a /be, 3, 3. 2 9 9—3, a .' be, 3, 3. 



2 9 9— 3, 3, a.' be, 3. 19 —3, 3, 3, a / be. 



Taking the totals of these families of females abnormal by 

 addition of bristles we find normal cf cf 154, normal 9 9 125, 

 variants by reduction, 2 cf' cf and 5 9 9; variants by addition, 

 10 cf cf and 8 9 9. Thus the variants by reduction are 2.3% 

 while the variants by addition are 6%. 



From the averages of the reared stock we see there is a 

 tendency to vary both toward reduction and toward addition of 

 bristles and that this tendency is evidently of a hereditary 

 character, the mean being shifted in the direction of the parental 

 abnormality. 



