48 BRITISH LEPIDOPTERA. 



or reddish-violet band. Hindwings with lighter central area some- 

 times banded, as in H. eitphorbiae, with black transverse stripes ; the 

 marginal band and basal area darker ; the transverse stripes some- 

 times less distinct than in the latter species. The antennae, white 

 above and brownish beneath, exhibit no special feature. The head 

 and thorax are olive-green above, the latter rarely grey-haired as 

 in T. vespertilio, but always margined laterally with white. Abdomen 

 ashy-grey mixed with olive, with two alternately black and white 

 lateral spots and only insignificant differential characters; the white front 

 margins are wanting from abdominal segment 5 onwards. ■ The under- 

 side of abdomen and thorax are rose-red. The legs show no special 

 peculiarity. From T. hybr. vespertilioides, H. hybr. epilobii \s distinguished 

 by its olive-green thorax, which is ashy-grey in the former, and by the 

 darker and sharper bands of the forewings. The band along the outer 

 margin of H. hybr. epilobii is, moreover, more angular and passes 

 less gradually into the colour of the outer margin. The red of 

 the forewings is also more restricted, and the underside of the 

 forewings shows an oval black spot as in H. euphorbide and 

 H. dahlii. The larva is most like that of H. eitphorbiae, and 

 aorees with it also in form and mode of life. When full- 

 grown it is black, covered on the back and sides with innumer- 

 able small yellowish or yellow-reddish spots or points. These 

 spots are inclined to disappear, yet specimens without them 

 but rarely occur. The larva of H. hybr. epilobii has, like that 

 of H. eitphorbiae, a red, sometimes reddish-yellow, stripe, which 

 runs along the middle of the back, and is sometimes represented 

 only by faint remnants on the 3rd and 4th segments. On the sides 

 of the dorsal area are, on each segment, two whitish- or yellowish- 

 red oval or round spots standing one above the other; they are 

 margined with black, and the lower of them is always much smaller 

 than the upper. Beneath these spots there is sometimes a further 

 row of very small dots. Above the legs runs a stripe composed 

 of red spots, but this likewise has a tendency to disappear. The 

 yellowish-red or yellow- brown venter also exhibits, medially, 

 some rather dark red or reddish stripes. The spiracles are 

 oval, pure white or yellowish-white, with black margins. The 

 horn on the nth segment is very small, and coloured red 

 in its lower third; its two upper thirds are black. Head, anal pro- 

 legs (" Nachschieber";, and anal-flap likewise red, the former some- 

 times with red sutures. The legs are also of a reddish colour, 

 exteriorly overlaid with black. Larvae also occur, which are 

 distinguished by an unicolorous black head and unicolorous 

 black horn, and in which the dorsal line is very narrow and 

 often only reaches to the 3rd segment, and in which, further, only 

 the thoracic legs are black-coloured at the tip ; but, in other 

 respects, these specimens agree with the others. The larva of this 

 hybrid differs from that of //. euphorbiae (with which, but 

 for its occurrence on Epilobium, it might easily be confused) in 

 having its horn less strong and scarcely half as long as in the 

 latter species. The larva is found at large from July to September 

 on Epilobium angustifolium^ E. dodonaei and E. fleischeri^ as well 

 as on other species of Epilobium. It is full-grown at the beginning 

 of September, and rests partly at the foot and partly on the stem of 



