LEPIDOPTEKA HETEROCEEA. 



BUTTERFLIES and MOTHS, Lepidoptera, are for the most part easily 

 distinguishable from other insects by : (1) the maxillae being pro- 

 duced into a tubular proboscis, which, however, is entirely obsolete 

 in some groups, such as the Psychidce, ffepialidce, Phaudince, 

 Saturniidce^ and some SesUdce, Pyralidce, &c. ; (2) by the mandibles 

 being obsolete except in the low forms (Micropterygidce) and a few 

 Tineidce ; (3) by the broad, regularly veined wings, nearly always 

 covered with minute scales, which are modified hairs, all the grada- 

 tions between the extreme forms of hair and scale being often 

 found on the same insect ; the females, however, of Psychids and 

 some Lymantriidce, Geometers, Tineas, &c. are wingless. 



The Larvae are cylindrical and worm-like, consisting of a head 

 with biting mandibles and eleven somites ; they have three pairs of 

 corneous, jointed, thoracic limbs, and from one to five pairs of 

 abdominal fleshy prolegs, the legs being but rarely absent, as in 

 most Psychidce ; most of the somites have paired, lateral, valved 

 stigmata, for conducting the air-supply to the tracheal system, 

 which ramifies throughout the body. The Larvae, when full-fed, 

 turn to Pupae, in which stage the head and thorax are soldered 

 together, as are also the appendages of the head and the limbs. 

 During this stage the whole of the tissues of the body undergo 

 degeneration into a liquid fatty substance, except the nerve-centres 

 and some bodies attached to them known as " imaginal disks," 

 which are the rudiments of the future body, wings, and legs, and 

 which, by absorbing the products of the degenerated tissues, gradu- 

 ally grow and build up the perfect insect till ready to emerge from 

 the Pupa skin. 



The Heterocera, or Moths, in their perfect stage, may be known 

 from the Ehopalocera, or Butterflies, by the latter having knobbed 

 or dilated antennae, which in all the families except Hesperiidce have 

 an abruptly rounded extremity ; in most Hesperiidce the knob of the 

 antenna is produced into a hooked tip, gradually fining to a point, 

 and this form of antenna is found in some moths, such as the 

 Castniidce and some Sesiidce, but in these families the " frenulum " 

 or hook for securing the hind wings to the catch or " retinaculum " 

 of the fore wing is always present. This is never developed in any 

 butterfly, whilst the families of moths that have the frenulum 

 absent, the Saturniidce, Bombycidce, Hepialidce, Lasiocampidce, some 

 Callidulidce, &c., never have the antennae knobbed. Home other 

 families of moths, such as the Sphinyidce, and in a lesser degree the 

 Ayaristidce, have the antennae gradually thickened into a club ; but 

 this is very different from the abrupt knob of butterflies, and in 

 these moths again the frenulum is always present. 



The head of a Lepidopterous insect consists of three pieces the 

 occiput or basal piece lying behind the ocelli, the epicranium 



VOL. I. B 



