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7. DESCRIPTIONS OF SOME SPECIES OF LEePIDOPTEROUsS INSECTS 
BELONGING TO THE GENUS OIKETICUS. 
By J. O. Wrestwoop, F.L.S. 
(Annulosa, Pl. XXXTV.—XXXVII.) 
It may probably be regarded as one of the settled axioms in na- 
tural history, that there is not a single character which has been em- 
ployed to distinguish any group of considerable extent, which is not 
liable to be effaced or even contradicted by some one or more of the 
members thereof ; thus, whilst we have quadrupeds without legs, and 
birds without wings, the great division of annulose animals charac- 
terized by the possession of articulated feet contains great numbers 
of species which are entirely destitute of those organs ; and in like 
manner the secondary division of the Annulosa, distinguished by the 
possession of wings in the final state (or the Ptilota of Aristotle), ex- 
hibits to us many species which never gain instruments of flight. 
Instances, however, in which both these grand characteristics are 
absent, are of the greatest rarity. Of wingless Ptilota examples oc- 
cur in most of the orders, as in the female glow-worm among the 
Coleoptera ; the neuter ant and female Mutil/a among the Hymenop- 
tera; many of the smaller grasshoppers and locusts among the 
Orthoptera; some of the Gerride among the Hemiptera; the 
genera Boreus and Termes in the Neuroptera; the female Coccus 
among the Homoptera; the genera Chionea and Borborus among 
the Diptera ; the Stylopzde, in the order Strepsiptera, and the females 
of various moths, as in the genera Orgyia and Cheimatobia, as well 
as in Otketicus of L. Guilding. Amongst these exceptions it will be 
remarked that the majority are cases in which only the females are 
wingless, whilst all except Coceus, Stylops, and Otketicus possess arti- 
culated feet in the wingless state. These three genera would therefore 
be regarded, if we considered only the adult state of the females, as 
the most degraded instances of apiropodous Ptilota. But such an 
opinion cannot be maintained, since the early states of these insects 
exhibit as high an amount of organization as those of any of the other 
insects in the orders to which they respectively belong, their peculiar 
characteristic being, that, whilst in the great mass of winged insects 
there is always a gradual evolution of structure, by which at length 
wings and legs are developed, these particular individuals, destined 
ultimately to appear in such a degraded condition, not only gradually 
lose their powers of evolution, but are subjected to a power of absorp- 
tion by which the limbs which they at first possessed are gradually 
reduced in size and ultimately entirely lost, till the animal retains only 
the appearance of a short sluggish vermiform animal, in which not 
only are the wings and legs but also the antenne and the organs of 
the mouth almost or entirely obliterated, and even the articulated 
condition of the body nearly lost. 
Such is the apparently helpless condition of the females of a rather 
extensive group of moths, which have been long well known to German 
entomologists under the name of Sacktragers, of which the smaller 
species constitute the genus Psyche, whilst some of the larger were 
