LEPIDOPTERA. 475 



smooth- The caterpillars usually have but ten feet; the others present 

 two more, and those at the extremity always exist. Their peculiar mode 

 of progression has caused them to be styled Geometras, or Measurers. 

 When about to advance, they first cling- with their anterior or squamous 

 feet, then elevate their body so as to form a ring, in order to approximate 

 the posterior extremity of tlie body to the anterior, or that which is fixed; 

 they cling- with the last feet, disengage the first, and move the body for- 

 wards, when they recommence the same operation. Their attitude when at 

 rest is singular. Fixed to a branch of some plant by the last feet only, their 

 body remains extended in a straight line in the air, and absolutely motion- 

 less. So closely does the skin resemble the branch in its coloui' and ine- 

 qualities, that it is easy to confound them. In this way and at an angle of 

 forty- five degrees, or more, with the hmb to which they are attached, these 

 animals remain for hours and even days. 



The chrysalides are almost naked, or their cocoon is extremely thin, and 

 poorly furnished with silk. 



This section, exclusive of the caterpillars, contains but one subgenus, or 

 Phaljena proper. 



8. The Deltoides, Lat, consist of species very analogous to true Pha- 

 Ixnae, but whose caterpillars have fourteen legs, and roll up leaves. In the 

 perfect Insect the Inferior palpi are elongated and recurved. Its wings 

 and body, on the sides of which the former are extended horizontally, 

 form a sort of delta, marked by a re-entering angle In the posterior side, or 

 appearing to be forked. The antennae are usually pectinated or ciliated. 



The Deltoides form the subgenus Hebminia, Lat. 



9. The TiNEiTEs comprise the smallest species of this order. Their 

 caterpillars are always closely shorn, furnished with sixteen feet at least, 

 and rectigrade, living concealed in dwelhngs fabricated by themselves, either 

 fixed or movable. Here the wings form a sort of elongated and almost 

 flattened triangle, terminated by a re-entering angle; such are the Pyra- 

 lides of Linnaeus; they have four distinct and usually exposed palpi. There, 

 the superior wings are long and narrow, sometimes moulded on the body, 

 and forming a sort of rounded roof to It, sometimes almost perpendicularly 

 decumbent and laid on the sides, and frequently raised or ascending pos- 

 teriorly like the tail of a cock. In both cases the inferior wings are always 

 wide and plaited. These species also frequently have the four palpi ex- 

 posed. 



All the caterpillars, whose habitations (sheaths) are fixed or immovable, 

 are the Pseudo-Tinem of Reaumur; those which construct portable ones, 

 which they transport with them, are true Tinese. 



The substances on which they feed, or on which they reside, furnish the 

 materials of the structure. 



Of those sheaths which are composed of vegetable matters, many are 

 very singular. Some, like those of the Adelse, are covered exteriorly with 



