Other Kinds of Hybridizing' 161 
forms, one with the other without horns. There is a large and a 
small form of earwig. Papilio glaucus has two forms of females, 
one yellow, the other black. The latter is found over the south- 
ern range of the species. “In this region both yellow and black 
forms have been reared from eggs produced by a single female.” 
Fic. 17. 
A number of cases are known in the higher plants, and their 
inheritance has been examined in a few instances. These are all 
hermaphroditic forms in which two kinds of flowers — both pre- 
ducing ova and pollen — are present on the same or on different 
plants. The European cowslip, Primula veris,occurs in two 
forms, the long-styled and the short-styled (Fig. 17). Each 
plant bears flowers that belong to one type only; the two types 
M 
