xii EuRorEAx Butterflies axd AfoT/rs. 



Tlie higher or lower temperature of the season is also not without some influence. In those 

 species whose larvse will find nourishment during the same year, the period of developm-jnt is 

 generally from eight days to four weeks; but in those species which lay their eggs so late in the 

 season that the food-plant of the larvse would have died down or shed its leaves by the time 

 that they were hatched, if their development was as rapid as in the other case, the eggs do not 

 hatch until the following spring, at the time when the food-plant is also unfolding itself. 



When the -period for hatching has arrived, the young larva bores through the shell, in which 

 it has previously lain coiled up, and enlarges the opening by gnawing it away till it can creep out, 

 when it not unfrcquently completes its task by devouring the empty egg-shell before tasting any 

 other food. 



LARV^. 



Siae and External Structure. — The body of the larva resembles a long cylinder, flattened off 

 on the under surface. It is, on the whole, of equal thickness throughout, but frequently becomes 

 rather thinner at each extremity. A few larvse are egg-shaped or woodlouse shaped (PI. 14, 

 Fig. 2, a) ; and those of the small moths, which mine in tlie substance of leaves, are generally 

 quite flat. A larva consists of thirteen joints, one behind another, separated by more or less 

 perceptible divisions, and sometimes by deep incisions. The joints are called segments, and the 

 first forms the head. Continental entomologists reckon twelve segments only, counting the head 

 separately. 



The head (caput) is always conspicuous, and is formed of a horny substance, but differs 

 very much in size and shape. It is seldom small and contracted, but is generally distinctly 

 separated from the ne.xt segment. Its shape is generally roundish, but is sometimes flattened, 

 truncated, or triangular. In the larvje of Gcoinetrce it is often produced into two angles at the 

 sides; and in the genus Apatura it is provided with two triangular horns (PI. 11, F"ig. 2, a). It 

 consists of two lobes, generally hemispherical in shape, which are separated above by a longitu- 

 dinal division, and divide in front near the mouth, where they enclose the basal portion of the 

 head, or clypcus. These lobes have frequently been called " eyes," but cannot be regarded in 

 this light. The true eyes {ocelli) are merely small, shining, roundish elevations on each lobe, 

 six of which are arranged in a semi-circle on each side of the mouth ; and they can only be 

 distinctly seen with a magnifying-glass. The clypeus is bounded beneath by the upper lip 

 (labnuu), under which the horny jaws {mandibles) are placed on each side, which serve for 

 biting. At the base of the latter are placed the feelers {antenna;), two small, pointed, movable 

 projections, generally four-jointed ; and beneath the mandibles the membranous lower lip {labium) 

 is united above with the lower jaws {maxilla:) and with two small four-jointed organs called 

 "maxillary palpi," and underneath on the inside with the two-jointed "labial palpi." At the 

 extremity of the lower lip is a horny, perforated projection called the spinneret, from which 

 issue the silken threads which form the cocoon. 



The rest of the body of the larva is covered with a soft and often wrinkled skin, and 

 is capable of being moved in any direction. The three segments after the head correspond to 

 the thora.x of the fully-developed insect; the first corresponds to the pro-thorax; the second to 

 the meso-thorax; and the third to the meta-thorax. These are called thoracic segments, and the 

 remainder, abdominal segments ; the last is called the terminal segment. The segment behind the 

 head is often covered with a horny plate, the scutellum; but the remaining segments only exhibit 

 a similar structure in a few genera. The last segment has a triangular or crescent-shaped flap 

 above the anus, called the abdominal fold, which is also horny in many species. Besides this, 



