The diurnal or Heliconean Hawk-mouths, form one of the most natural and remarkable groups among Lepidopterous insects. They fly during the heat of the day; and, (as representing in their own family the tribe of _Phalænides_) they have much of the general appearances of moths. In their slow flight, long transparent wings, and proneness to imitate death on being handled, they afford a most beautiful analogy to the Heliconian Butterflys. Both have their chief metropolis in equinoctial America, and both find their prototypes in the lovely family of _Erycinidæ_. It is really surprizing that searchers after the _natural_ system, should have overlooked such a group. Among the comparatively few genera of this division, found in India and the adjacent islands, is that now first defined: and we illustrate it by a new and very rare species, even in its own country. It was twice seen by Mr. Cunningham, on the North West Coast of Australia; once in shady woods descending to the shores of York Island, and again in nutmeg woods adjoining Brunswick Bay. The form of the wings, which strongly resemble those of the sub-family _Papilionæ_ will immediately distinguish this from all the American genera. The plant, _Pattersonia glauca_, is of a sub-genus also peculiar to New Holland. * * * * * * [Illustration: LEPTONYX _macropus_. _Great footed Babbler._] LEPTONYX macropus _Great-footed Babbler._ ---- Family Merulidæ. Sub-family Crateropodinæ. Genus Malacocircus, Sw. Sub-genus Leptonix. (_The Rasorial type._) _Nob._ SUB-GENERIC CHARACTER. Feet of extraordinary size and thickness, all the anterior toes of nearly equal length; the claws long, slender, and but slightly curved. Tail slightly rounded, of fourteen feathers. Wings very short. ---- SPECIFIC CHARACTER. _Above brown beneath whiteish, with transverse undulated lines; breast and rump, rufous brown; chin, stripe above and beneath the eye, whiteish._ ---- For the use of this new and singularly formed bird, we are indebted to Professor Hooker, who, with his usual liberality, has recently sent for our inspection, a valuable box of Chilian birds, most of which are undescribed. They form the foundation of his son's, Mr William Hooker's collection, who has already commenced with much zeal the study of this interesting science. All the rasorial characters are strikingly displayed in this extraordinary type; which exhibits the greatest developement of the foot of any insessorial bird yet discovered. It no doubt lives entirely upon the ground; for the feet are formed precisely on the same model as those of _Menura_ and _Orthonyx_, both of which are the rasorial types of their respective circles, and are consequently representatives of _Leptonyx_: the same analogy explains its resemblance to a partridge, and more distantly to the sub-genus _Erythaca_ Sw. by its rufous breast.