3044 THE JOINTED ANIMALS 



not easy of solution. The pair of thread-like, many-jointed organs, which take 

 their origin from the side of the epicranium, just above and within the compound 

 eyes, are among the butterflies, with the exception of the family HesperiidcB, thread- 

 like, and abruptly clubbed at the apex. In the latter family they are gradually 

 thickened toward the end, which often terminates in a hook-like point. The moths, 

 however, as their name Heterocera implies, furnish us with far greater variety in 

 the form of the antennae; quite apart from the fact that they differ in both sexes of 

 the same species, thread-like, for instance, in the female, pectinate in the male sex, 

 we find at least ten different forms of antennas among members of this section: 

 Filiform, or thread-like, gradually tapering to a point; fusiform, broadened from 

 the base onward to the tip, which is again narrowed; dilate, narrow from the base 

 to about one-third its length, then rather suddenly enlarged, and again narrowed 

 at the tip; ciliate, clothed with the finest hairs; setigerous, each joint furnished with a 

 bristle on either side; setigerous and tiliate, furnished with both fine hairs and paired 

 bristles; fasciculate, each joint furnished with a group or tuft of short bristles, like 

 a small brush; dentate, or toothed, each joint produced into a sharp tooth-like 

 process at the side; lamellate, where each joint is produced at the margin into a 

 small plate-like prominence; serrate, sawlike, each joint produced into a short sharp 

 point at the side, giving the whole antennae the appearance of a saw, the teeth are 

 not so long as in the dentate antennas; pectinate, each joint furnished with long 

 plume-like hairs, or a pair of such on either side. 



The second division of the body, like that of the Hymenoptera, is 



. , composed of three closely-united rings, each bearing beneath a pair of 



legs, while the posterior pair carry also on their upper or outer sides, 



each a pair of well-developed wings. The prothorax bears the fore-legs. The 



mesothorax the mid -legs and fore- wings. The 

 metathorax the hind-legs and hind-legs. The legs are 

 not used normally for walking, but are chiefly serv- 

 iceable for clinging to objects while settling or at rest. 

 They do not call for any special mention; and are not of 

 great account for purposes of classification, except in the 

 butterflies, where in the case of the males of the three 



I.EFT FORE-WING OF A 



NOCTUA MOTH. families Nympkaluhe, Erycinidce, and Lyceemda, the 



a, b, c, h, indicate the normal fore-pair are much reduced in size, being in some cases 



position of the transverse almost rudimentary, 

 bands, a. costal margin; /. 



inner margin; d. discoidai By far the most important structure in the eyes of 



spot; e. reniform spot. the general natu ralist, though not necessarily so in the 



opinion of the expert, are the beautiful membranous, scale-clad pinions. These 

 give the distinctive characteristic to lepidopterous insects, and render them so fas- 

 cinating to the lover of nature. Broad and ample on the whole among the butter- 

 flies, more narrowed as a rule among the moths the hawk moths for instance 

 they are formed of the finest transparent membrane stretched out between the stiff 

 rib-like nervures, or, more properly speaking, veins, which carry the nutritive fluids 

 from the central system to all parts of the structure. The nerves, as custom will 

 persist in terming them, in the butterflies take a bow-like or ellipsoidal sweep from 



