EXPERIMENTS IN HYBRIDIZATION AND TEMPERATURE. 347 



parent, could not be ascertained in any of the numerous cases 

 investigated, but, on the contrary, generally a decrease. 



7. The broods of secondary hybrids, whether from an in- 

 pairing of these forms (No. 18, PI. IV. fig. 3 and footnote 5) or 

 from crossing with a true Saturnia female (No. 19, PL IV. fiig. 

 5 and footnote 6), produced up to the present only males, which 

 were certainly capable of reproduction. 



As already stated, among certain secondary hybrids are to 

 be found relatively numerous gynandromorphic specimens. We 

 say gynandromorphic and not hermaphrodite specimens, because 

 the anatomy of a number of these forms shows (it is true only 

 such have been investigated as tended more to the female type) 

 the male-female characters only in secondary sexual characters, 

 i. e. the antennae, wing form, and coloration, and the outer 

 organs of the genital apparatus, but not in the primary sexual 

 characters, that is, the egg germs. The latter showed only a 

 shght degeneration and malformation. In other respects they 

 were entirely of one sex. 



There is no question here of true hermaphrodites, as only 

 those individuals are regarded as such which having partially 

 male and partially female characters ; this peculiarity is also to 

 be found in the sexual organs. 



In order to go thoroughly into this extraordinary fact, the 

 results of our experiments were as follows : — 



1. The male hybrid of S. jxivonia S' xpyri ? crossed with 

 S. pyri ^ No. 11 resulted in no brood in more than 60 per cent, 

 of the pairings, and in the best case only 1 per cent, of living 

 larvae, of which many died. 



Of the eight imagines bred, five were gynandromorphic, 

 probably resulting from four different broods. 



2. The same male crossed with S. pavonia ? No. 10 resulted 

 in no brood in 33 per cent, of the copulations; the fertile ones 

 producing between 4 to 62 per cent. 



The resulting larvae were not very healthy. 



Of fifty-four imagines bred up to now, twelve are gynandro- 

 morphic (PI. III. fig. 3).^ Nine broods produced one gynandro- 

 morphic specimen each, and the 10th brood three. 



3. The males of the hybrid S. pavonia <? x spini ? crossed 

 Wii\ipavonia ? yielded without exception broods No. 13, amounting, 

 in cases where an account was kept, to 16 to 84 per cent. 



^ The gynandromorphic characters of the individuals of this hybrid 

 form (PI. III. fig. 3) can be easily seen from the figure. On the upper side, 

 the right fore wing, the left fore and hind wings, and the abdomen are 

 entirely of the female coloration, the right hind wing male. The antennae are 

 both nearly male, but with somewhat shorter feathering than usual. The male 

 genital claspers are present in a rudimentary form at the end of the abdomen. 



The under side of the wings and body show male and female characters 

 mixed up with one another, except the right hind wing, which here again is 

 entirely male. 



