84 THE GENERA OF BRITISH MOTHS. 
callis, and Odontopera, forming three distinctly graduated steps in the depth of the pectinations, which though 
strong, are very shallow in Odontopera Bidentata. The double-toothed projection at the prominent part of the 
edge of the front-wings of the insect is expressed in the specific name. The hind-wings also begin to be dentate, 
but not to the extent which we shall meet with in the next genus. The Caterpillar (No. 6) feeds on Alder and 
other trees. There are two broods of them ; the perfect insect appearing both in April and June. It is common 
every where. 
The genus Odoptera. In this genus we find the types of the Sub-Family Odopteridi ; the deeply indented 
edges of the wings giving them a peculiar and distinct character, such as serves very commonly as the leading 
typical mark of a Sub-Family. There are eight British species in this well defined genus, of which five are 
represented in the annexed Plate. 
Odoptera Alniaria (the Large Thorn, No. 7) is by far the largest British insect belonging to this genus ; but 
its right to be considered really a British species, is scarcely as yet sufficiently established. There is, however, 
a specimen in the British Museum, captured in England ; and specimens have been taken at Brighton, Margate, 
and near the North Foreland Lighthouse ; possibly, stragglers from the opposite shores brought over in a gale, 
for the insect. is common on the Continent. The specimen in the Museum is a female, but the Continental 
specimen from which my drawing was made, is of the other sex, as indicated by the strongly pectinated antenne. 
The Caterpillar is described as brown marbled with whitish, and having a protuberance on the back of the 
seventh and at each side of the twelfth segment. It feeds on Alder, Birch, and other trees. 
Odoptera Tiliaria (the Canary-shouldered Thorn, Nos. 8 and 9) may be distinguished at once by the colour 
of the silky hairs with which the thorax is clothed, and upon which the popular name of this pretty species is 
founded. It is the Geometra Canaria of Hiibner. The Caterpillar (No. 9) is one of the most curiously formed 
of the genus, though still bearing a strong family likeness to its relatives. The great enlargement of the third 
segment from the head, where it joins the last pectoral legs, and the sharp protuberances on the back, increasing 
in size as they reach the thickened hinder part of the body, give it a curiously rugged appearance, somewhat 
similar to that of the Caterpillar of O. Zwnaria, in which, however, the protuberances are not so remarkable. It 
feeds on Birch and Oak, and the Moth appears in August. It is very common. 
Odoptera Erosaria (the September Thorn, Nos. 10 and 11). This species has been figured principally on 
account of the large size and somewhat distinct characters of the Caterpillar. It appears in September, as its 
popular name imports; and though less abundant than some of the preceding, is not uncommon. Lewes, Lynd- 
hurst, York, and other widely distant localities, are cited as places of its recent capture. 
Odoptera Angularia (the August Thorn, Nos. 12 and 13) has the wings more deeply indented than 
others of the species; on which account I give a figure of it, as being in this respect the typical species of the 
group in so far as the British species are concerned. The Caterpillar feeds on several trees. The perfect insect 
appears in August, and is very common. Worthing, Brighton, Exeter, York, and other places, are Sired where 
it is ordinarily abundant. 
Odoptera Iitustraria (the Purple Thorn, No. 14). This species is the most richly coloured, and in that 
respect the handsomest of the whole group. The Caterpillar feeds on oak, and the Moth appears in May and 
June. It is much more rare than either of the species ; being found sparingly in the woods of Kent, in the New 
Forest, and in Devonshire. 
There are three other species. 0. Fuscantaria has the front-wings narrower and less dentate, and they 
are but little variegated, being deep ochre with a nearly solid band of a deeper colour at the external edge, 
and two narrower transverse streaks; the hind-wings being dusky-brown. 0. Lunaria closely resembles 
Iilustraria, but is smaller and much less richly coloured. O. IlZwnaria is also somewhat like O. I2lustraria, 
but has a broadish pinkish stripe down the front of the fore-wings and the hind-wings are only marked by very 
pale transverse bands. Many varieties of these last, and of the other species, were formerly ranked as distinct 
species under various names which have now disappeared from the British Catalogue, except as synonyms. 
