SCALE-WINGED INSECTS 



709 



SCALE-WINGED INSECTS, OR BUTTERFLIES AND MOTHS 



BY W. F. KIRBY, F.L.S. 



BUTTERFLIES and MOTHS are easily distinguished from other insects by many very obvious 

 characters, and a considerable number are remarkable for the beautiful and varied colours of 

 their wings. These are, as it were, tiled with overlapping scales, attached to the membrane 

 by a slender stem ; hence their name, Scale-winged Insects. These scales differ very much 

 in shape, sometimes being long and slender, and almost hair-like, while at other times they 

 are widened at the extremity, like a battledore, or they may be short and broad, like a fan 

 or a shovel. Different forms of scales are found on different parts of the wings of the same 

 insect; and some forms of scale are peculiar to the male, as are usually the dense tufts of scales 

 found on the fore wings of the Skipper Butterflies, and on the hind wings of the Chrysippus 

 Butterfly. The varied colours of these scales are due partly to pigment, interposed between the 

 extremely delicate double or triple tissues of which the scales are composed ; or, more rarely, to 

 the refraction of light from the surface of the scales themselves, or, as has recently been stated, 

 to different coloured scales alternating so that the varying colours are visible at different angles, 

 as in the metallic " shot " colour of the Purple Emperor Butterfly, and in various species 

 found in South America and other countries. In the case of the Purple Emperor, and in 

 many other butterflies, this "shot" colouring is confined to the males. Indeed, as a rule, 

 female butterflies and moths are larger than the males, but far less brilliantly coloured than 

 their mates. There are, however, many species in which the sexes differ little in size or 

 colour ; but it only rarely happens that the female is more brightly coloured than the male. 



The bodies of butterflies and moths, the legs, and often more or less of the base or 

 borders of the wings are clothed with hair or hair-like scales. These insects have a long or 

 short proboscis, through which they imbibe their food, which consists of the honey of flowers, 

 the sap of trees, or moisture from the ground. Like other insects, they have six legs in the 

 perfect state ; but in some species either the front or hind pair becomes more or less rudimentary, 

 especially in the males. 



Butterflies and moths pass through four stages. The egg is laid by the female on 

 some plant which will provide 

 suitable nourishment for the 

 caterpillar. A caterpillar, which 

 is the next stage, is a jointed, 

 worm-like creature with sixteen 

 legs ; those corresponding with 

 the legs of the perfect insect 

 are horny, and a pair is placed 

 on each of the first three 

 joints behind the head. The 

 next four pairs, called " pro- 

 legs," are thick and fleshy, and 

 a pair is placed under each of 

 joints seven to ten (reckoning 

 the head as joint one), the last 

 joint of all being provided with 

 a pair slightly differing from the 

 others, and called "claspers." In 

 many young caterpillars, how- 

 ever, and also in the full-grown 



.,< r -1 11 Vholv by J. Edwards] 



caterpillars of a considerable LEAF-BUTTERFLY 



number of moths (especially Tkfu hutter ft iei are rtmar kably like certain lea-vet that it h almost impossible distinguish 



among those with slender * 4fW .-* 



