Mr. J. O. Westwood's Description, Sfc. 195 



XXIX. — Description of a Hybrid Smerinthus, with Re- 

 marks on Hybridism in general. By J. O. Westwood, 

 F.L.S. 



[Read 1st January, 1838.] 



The account given by Mr. House in the preceding article, of the 

 production of hybrid specimens by a forced union of Smerinthus 

 ocellatus $ , and PopuU 5 , is especially entitled to observation, as 

 being the first recorded statement of any satisfactory result arising 

 from such an adulterous marriage, as this unnatural union between 

 two distinct species of insects has been not unaptly termed, in 

 this class of animals. 



The following is a precise description of the appearance of one 

 of these hybrids, which, in conjunction with the figure of it, which 

 I beg to offer to the Society, exhibiting the upper and under view 

 of the wings, will give an idea of its peculiar relations to each of 

 its parents. (See Plate XT. fig. 1.) 



The two specimens which I have examined would, from the 

 form of the body and the pectination of the antennae, be regarded 

 as male insects. The expanse of the wings in both is three inches. 

 In the outline of the wings the character is intermediate between 

 the two species, the external margin being nearly similar in its 

 general figure to that of Ocellatus, but being notched, although far 

 less strongly, than in Popttli. The markings of the fore wings 

 are almost identical with Populi, the outer margin of the dark 

 discoidal central broad bar is more irregular, and is succeeded by 

 two waved fasciae, the first of which is less conspicuous than the 

 other. The markings of the hind wings, on the contrary, more 

 nearly resemble Ocellatus ; the pink colour of the base is however 

 exchanged for the dark ferruginous colour as in Populi, extending 

 more generally over the wing than in the latter species. In the 

 place, however, of the beautiful and clearly marked grey, silvery, 

 blue, and black eye oi Ocellatus, there is a large indistinctly sufl^used 

 black patch, in which is an obscurely defined dark leaden coloured 

 eyelet. On this pair of wings are no traces of the transverse bars 

 of Populi. On the under side the markings of all the wings re- 

 semble those of Ocellatus more nearly than those of Poptdi, there 

 being four waved fasciae aci'oss the disc of the posterior pair. 

 Moreover the basal half of the fore wings is, as in Ocellatus, of the 

 same colour as the base of the hind wings above, being of a dark 

 ferruginous hue, which is far more strongly coloured in one than 



