300 BRITISH LEPIDOPTERA. 



Genitalia. — (i) A. populi 3 . The superior harpes are rounded and full, having 

 an acute angle on the inner margin. The inferior harpes bifurcate at the extremity, 

 the inner hook being elongated, the outer hook short and abrupt. The uncus is 

 elongated and rounded at the tip. The flap is large, gently tapering to a point. The 

 penis is irregularly curved, surmounted by about 30 or 40 spines (Ent. Rec, x.. pi. iii., 

 fig- 3)- ( 2 ) •$• ocellata* 3 . — The superior harpes broad and rounded, having an acute 

 angle at the inner margin. The inferior harpes short and toothed on the inner 

 margin and terminated by a single pointed hook. The outer margin is indented 

 just past the middle, and again nearer the extremity, forming an acute angle. 

 The uncus is abruptly elongated, terminating in a point or beak. The flap is 

 gently pointed, almost forming a right angle, with the tip slightly rounded. The 

 penis is bulbed, slightly produced at the base, it then ascends almost parallel, having 

 a sharp hook on the lip, and is surmounted with a large number of short, thin spines 

 (loc. cit., pi. iii., fig. 2). (3) M. tillae 3 . — The superior harpes are short and square. The 

 inferior harpes are bifurcate at the extremity, with two equal projections. The uncus 

 is broad and r< unded, slightly indented at the lip. The penis is long and slender, 

 widening at the base into two lobes, surmounted by two short spines (loc. cit., pi. hi., 

 fig. 1). (4) A. populi 2 . — The organs consist of two lobes, covered with tubercles, 

 each of which emits a short, stiff hair, and have somewhat the appearance of a 

 spider's spinneret ; there is also the ovipositor, which consists of a short tube; 

 this is placed about three parts of the way down the final segment (loc. cit., pi. iii , 

 fig- 6). (5) S. ocellata 2 . — The female of this species has so nearly similar 

 organs to those of the last, that further description is unnecessary' (loc. cit., pi. iii., 

 %• 5) (Pierce). 



Gynandromorphism is very prevalent in Amorpha populi and 

 Smerinthus hybr. hybridus. Schultz notes the following (III. Woch. 

 filr Ent, I, pp. 367—368; ii.; pp. 393— 395; ™-> PP- I S5— I 3l) ■ 

 Mimas tiliae, 3 examples; Smerinthus ocellata, 2; S. hybr. hybridus, 

 7; Amorpha populi, 66. 



Parthenogenesis is reputed to have occurred in Mimas tiliae and 

 Smerinthus ocellata (see Ent. Rec., vi., p. 71). 



One of the most interesting features of the Amorphid genera is 

 the comparative ease with which some of the species hybridise. 

 The best known hybrid is Smerinthus hybr. hybridus (ocellata 3 X 

 populi 2 ), the reciprocal cross Amorpha hybr. inversa (populi X 

 ocellata) being much more rarely obtained. The crossing of Amorpha 

 austauti $ , the large north African representative of A. populi, with 



* 6". hybr. hybridus (ocellata 3 x pcpuli 2 ), 3 . — The superior harpes are 

 narrower, rounded, and have the acute angle on the inner margin. The inferior 

 harpes are long and simple, gently tapering into a long thin point, straight on 

 the outer margin. The uncus is abruptly elongated, terminating in a pointed beak. 

 The flap is produced, roundly tapering to a point. The penis is almost bulbed at 

 the base, proceeds in a parallel direction, and is surmounted with about 20 

 small spines bunched together. In point of size, there is very little difference in 

 the three (ocellata, hybridus and populi') (Ent. Rec, x., pi. iii., fig. 4) (Pierce). I would 

 point out that the genitalia of the male hybrids differ from those of the males of 

 both parental species, but the organs of the 2 hybrid tend towards gynandro- 

 morphism. On the other hand, the sexual organs of the pupae show no tendency 

 whatever towards a confusion of the sexes, nor do they differ in any respect from those 

 of S. ocellata or A. populi in this stage. This is, I suppose, only what might 

 have been expected, as the imaginal characters are subjected to the influences of 

 both natural selection and intra-selection, while the rudimentary pupal organs 

 escape all these influences, except the slow reducing action of intra-selection in the 

 embryonic stage (Bacot). It will be noticed that in no point does the 3 genital 

 structure of the hybrid agree with that of 3 At. tiliae, but we find the male hybrid, 

 to a certain extent, agreeing with S. ocdlata in the uncus, the hook on the lip 

 of the penis, and in the rounded portion of the apparatus at the base. The flap 

 rather approaches (vide, loc. cit., pi. iii) to that of A. populi, the lower portion of the 

 penis being divided between the two parent species, and partaking of the characters 

 of both. It will thus be seen that the apparently male specimens possess distinctly 

 male organs, all of which are highly developed and different from those of the 

 parents (Pierce). 



