EUMORPHIN^E. 45 



ticulata, in medio duabus fasciis obscurioribus et puncto albo instructis, 

 ciliis rubris unicoloribus. Alis posticis in margine ad angulum interiorem 

 incisura magna instructis, denticulatis, ciliis maculatis, in costis roseis, 

 radice usque ad medium fere nigris, dein olivaceis, fascia terminali 

 obscuriore. Some weeks since I received an insect exactly intermediate 

 between D. elpenor and D. porcellus. Exact comparison shows it to be a hybrid 

 between the two species. The size is exactly intermediate between the 

 average wing-expanse of elpenor and porcellns [elpenor 2101111.-23111111., porcellus 

 16mm. -18mm. )» 2t amounts to exactly 20mm. The body, in form and colour, 

 partakes exactly of the characters of the two. In porcellus, the colour of the 

 body is usually red, mixed with green on the front of the thorax, the upperside of 

 the "head is usually green, the underside of the abdomen is slightly tinged with 

 green ; the collar is always red. In elpenor, the ground colour of the body is 

 olive-green, a longitudinal band on the upperside of the abdomen, and its sides 

 red. The green thorax bears the 4 well-known red longitudinal bands, collar 

 and upperside of head are green. In addition, the form of the abdomen is 

 different in the two species, that of porcellus undergoes a quick and sudden 

 narrowing behind the middle, which is not the case in elpenor. The inter- 

 mediate form has head and thorax of elpenor, and, therefore, lacks the red collar. 

 The abdomen, too, is green as in elpenor, the sides red. The red longitudinal 

 band is wanting. On the other hand, the form of the abdomen, especially its 

 rapid narrowing towards the apex, is quite similar to the symmetrical proportions 

 in porcellus. The antennae are exactly those of porcellns ; in elpenor they are 

 always tinged with red on the hinder half, in porcellus white. Those of the 

 intermediate form are white, and are also not so long as those of elpenor. 

 The forewings share most precisely the characters of those of the parents. 

 Porcellus, as is well-known, possesses the strongly sinuated outer- and inner- 

 margin, which gives it its characteristic wing-form ; elpenor has not this. The 

 hybrid of which we are speaking has a weakly sinuate outer- and innermargin. 

 The border in elpenor is purely red, in porcellus, at least in the outer part, 

 chequered with white between the nervures. In the intermediate, there are 

 none of these white spots. The broad red area on the outer margin corresponds 

 in form with that of porcellus, the indentations on the inner margin thereof 

 are especially very strong and distinct as in porcellus. Further, the red areas 

 of porcellus are entirely wanting on the costal margin, on the other hand, the 

 red stripe bordering the costal margin of elpenor is not wanting. The two 

 oblique red bands of the latter are found in the intermediate form. They follow 

 entirely the same course as in elpenor, but their red is extremely indistinct and 

 pale, they are distinctly marked by the darker green border on the outside, 

 which elpenor also possesses and which stands off distinctly from the ground 

 colour of the wing. The red splash on the inner side of the inner oblique stripe 

 is distinctly present, as also the white spot between the costa and inner oblique 

 stripe. The upper wing thus approaches more in form and colour to elpenor^ 

 though with an unmistakable mingling of the characters of porcellus. In 

 colour it inclines more to the yellowish-green of porcellus. The hindwings are 

 in the highest degree characteristic. As- is well known, porcellus approaches 

 the genus Smerinthus in the cut of these. The sinuate hindmargin, the inden- 

 tation at the inner angle, the strongly sinuate inner-margin, and the white- and 

 red-spotted fringes, essentially distinguish it from elpenor, whose hindwings 

 have none of these characters— the fringes in particular being unicolorous white 

 throughout. Now, in the hybrid, the form of the hindwing is altogether that of 

 porcellus, not wanting the strongly sinuate outer- and inner-margin, whereby 

 arises the characteristic ' : tooth." The fringes likewise agree most exactly in 

 being red- and white-chequered. On the other hand the colour of the hind- 

 wings is more that of elpenor. The half of the wing is deep black as in that 

 species (in porcellus the black area is small and narrow). Thereto follows a 

 dirty reddish-green area, which in elpenor appears much more intensely coloured. 

 A suggestion of porcellus appears again in a darker marginal area which cor- 

 responds entirely, in form and extent, with the red marginal-band of the hind- 

 wings of porcellus. There is some indication of the narrow dark stripe which, 

 in elpenor, runs through the middle of the red area of the hindwings. Altogether 

 the hindwings show such an exact blending of the peculiarities of those of the 

 prototypes that on an exact consideration of them all doubt must vanish. It is 

 to be added that, on the hindmargin of the forewings, towards the inside, elpenor 

 has a tuft of black hairs which is margined externally by a white one that loses 

 itself in the margin of the wing. This structure is wanting in porcellus. The 



