STRUCTURE OF LEPIDOPTERA. 29 



and in this case those of the male arc always more developed than those of the female. An herma- 

 phrodite of such a species presents a very remarkable appearance when the antenna on one side is 

 pectinated, and that on the other is simple. The antennae are often clothed with hair or scales, and 

 the basal joint is larger and thicker than the others, except in the Butterflies and Sphinges. In some 

 genera of Tineina it is expanded into a scale, which partially covers the eye when at rest, and is 

 called the eye-cap. 



The parts of the mouth which ai*e best developed in Coleoptera and Hymenoptera are very slightly 

 developed in Lepidoptera, and are almost rudimentary. The only organs which demand attention 

 are the large and overhanging clypeus, the proboscis, and the labial and maxillary palpi. The upper 

 part of the mouth is formed by the small labrum, which is nearly concealed by the overhanging 

 clypeus, and the rudimentary mandibles. Below these is the proboscis, or tongue, which is generally 

 horny. It forms a spiral tube when not in use, but can be stretched out and plunged into the 

 corolla of a flower when the insect desires to feed. It is made of t\vo separate pieces throughout 

 its entire length, so that it can be separated and cleaned if there is any danger of its becoming 

 clogged. In many Bombyces the proboscis is nearly obsolete, whereas in the Sphingidce it is often 

 several times as long as the body, and is sometimes liable to become fixed in flowers and broken. 

 The proboscis corresponds to the maxillae of other insects. At the base of the proboscis are placed 

 the maxillary palpi, which vary in shape and size, and are usually composed of three joints, the 

 last being generally pointed. The lower portion of the mouth is formed by the small triangular 

 labium, on which the labial palpi are placed, which consist of from one to three joints, and are 

 rudimentary in most of the larger Lepidoptera. 



The structure of the thorax differs little from what we find in other insects. The prothorax 

 is very narrow above, but is broader below, where the fii'st pair of legs are attached to it. The 

 mesothorax is very large, and is divided longitudinally above. It bears the first pair of wings and 

 the second pair of legs. The former are attached beneath small thin plates called scapulae. The 

 metathorax is short, and generally consists of five small plates above. The last pair of wings and 

 legs are attached at the sides and on the lower surface respectively. 



The abdomen consists of nine movable segments, the hinder margin of each covering the base 

 of the next. The last segment contains the anus and the sexual organs. The male organ is enclosed 

 by two folds, and the female is sometimes provided with an ovipositor. Scent-fans, or scent-pouches, 

 are sometimes placed at the bass or extremity of the abdomen in the males. 



The whole body is more or less densely clothed with hair or scales, which sometimes form 

 conspicuous crests on the thorax and abdomen. 



The nervous system of the larva becomes much modified in the perfect insect. All Lepidoptera 

 have two cephalic ganglia, and the supra-oesophageal ganglion is furnished with convolutions. In 

 most cases there are two distinct thoracic ganglionic masses, the first simple, and the second 

 composite. Sometimes these are close together, and at other times they are more or less widely 

 apart. There are always four abdominal ganglia, the only known exception being in the case of 

 Hepialus humidi, which has five. 



The digestive system is also modified in the perfect insect. The intestine is much longer than in 

 the larva, and the long and narrow oesophagus is dilated into a large crop in the thoracic segments 

 which is generally filled with air. The stomach is short, oval, and very muscular, and the ilium is 

 long and narrow, and forms several convolutions, and is covered by the Malpighian vessels throughout 

 its whole length. The colon is large, and is often dilated into a caecum in front. The salivary glands 

 are simple elongated tubes, and correspond to the silk glands of the larva. 



The food of Butterflies and Moths in the perfect state consists of the honey of flowers, honeydew, 

 the exuding sap of trees, over-ripe fruit, &c. The great Death's Head Hawk Moth (Acherontia, 

 atropos) will sometimes enter beehives, to feast upon the honey. Nor is this the only enemy which 

 Bees have to fear among Moths; for there are several species of small Moths, the caterpillars 

 of which feed on wax in bee-hives, and often commit great havoc. Many Butterflies are 

 attracted by putrid substances, and others are fond of assembling, sometimes in great numbers, to suck 

 up the moisture from the damp ground. 



The senses of Lepidoptera are very acute. They are not unfrequently attracted by artificial or 



