42 INHERITANCE IN SILKWORMS, I 



vigorous rubbing to remove eggs of the adhesive egg races). Or in 

 rarer cases the eggs may be fairly firmly fastened. In other cases some 

 eggs may be firmly fastened and some weakly fastened. In others some 

 may be weakly fastened and some loose and the proportion of loose to 

 fastened may be slight to large. But the females showing these varia- 

 tions in the egg character are very few compared with those showing 

 the normal loose eggs condition. Matings were made pure and crossed 

 on the basis of these variations in the egg laying, and the results, 

 although the work has been only fairly begun, already show un- 

 mistakably the general character of the inheritance behavior of the 

 characteristic. 



This egg character or rather imaginal character of egg-laying is 

 not a Mendelian or alternative character in inheritance. The non- 

 adhesive condition exhibited by the Bagdad race however it may have 

 originated, either as sport or as selected fluctuating variation, shows 

 a plain tendency to change (back?) to the adhesive condition. From 

 those few pure Bagdad matings (out of many pure Bagdad matings 

 made) in which the female laid adhesive eggs, young were obtained 

 which on being mated together produced some adhesive eggs in almost 

 every case, and in most of these cases all the eggs laid were adhesive. 

 From crossed race matings in which the female was a Bagdad laying 

 adhesive eggs, young were obtained which, mated together, produced 

 almost exclusively adhesive eggs. It seems from this plain that the ad- 

 hesive egg character is very unstable, succumbing quickly in crossed 

 matings to the character adhesiveness, and tending even in pure 

 matings to throw partially or even completely (reversions?) the char- 

 acter adhesiveness. 



But when there are mated together hybrids produced by crossing 

 Bagdad with a non-adhesive egg race the young of these hybrids 

 usually lay non-adhesive eggs. That is, this is true in practically all 

 cases where the hybrids have for parents a Bagdad moth and a moth 

 of any one of six other different races used in the matings. But where 

 the parents were a Bagdad moth and a moth of a certain single adhe- 

 sive egg race, viz., Italian Salmon, the hybrids deposited sometimes 

 non-adhesive, sometimes adhesive eggs. 



This character is one exhibited only by the females, of course, but 

 capable of being transmitted through the males. Males of races laying 

 adhesive eggs when mated with Bagdad females (laying non-adhesive 

 eggs) may produce young tending to lay adhesive eggs. In other 

 cases the young from Bagdad males crossed with non-adhesive race 



