IXTKODCCTIOX. V 



and are then bent downwards, somewhat in the manner of a clasp-knife, and are called 

 plicate. 



The tongue is sometimes very strongly developed, especially in the Sphingidce, in which it is 

 often as long or longer than the body when extended. In some foreign species it measures little 

 less than a foot in length. But in most of the Bombyces, in many Tincina, and in some species of 

 other groups, it is only slightly developed, and sometimes only consists of two short and soft 

 threads. In other cases it is horny, and perceptibly rolled. 



The thorax is oval or square, and is sometimes broader than it is long. It is smooth, or more 

 or less convex, with the front angles or shoulders either rounded off (Fig. 4), obtusely angulated 

 (Fig. 5), rectangular, or with projecting angles (Fig. 7). There is often a tuft of hair or scales on the 

 thorax, behind the collar, especially in the Noctnce, which may be either smooth, raised, or divided 

 by a longitudinal furrow (Fig. 5). It is sometimes pointed, and in this case it is often produced 

 into a longitudinal ridge or crest (Fig. 7). We often find a truncated or divided tuft on the plate at 

 the end of the thorax (Fig. 5), or the back of the thorax is raised like a sort of cushion, and is 

 consequently often contracted longitudinally. 



The abdomen (Figs, i and 2, III) is cylindrical or tapering (Fig. 6), arched (Fig. 5), or flattened 

 (Figs. 4 and 7). It differs in length and thickness, and sometimes does not reach nearly so far as 

 the hinder angle of the hind-wings, while in other cases it extends much beyond it. Like the 

 thorax, the abdomen is frequently furnished with tufts of hair on the back, especially on the first 

 segments. Sometimes these tufts extend to the extremity of the body (as in Fig. 5) ; and we 

 occasionally find similar tufts on the sides and at the tip of the abdomen. The last is called 

 the anal tuft. 



The legs consist of three portions— the thigh {femur, Fig. 2, sk), the shank {tibia. Fig. 2, sn), and 

 the foot {tarsus, Fig. 2,fs). The femur is united by a small connecting ring, called the trochanter 

 (Fig. 2,sr), to the hip-joint, or eoxa, which is jointed to the pectus. The tibia is jointed to its 

 extremity, and the tarsus to that again. The femur and tibia consist of a single joint each, but the 

 tarsus has five movable joints, the first of which is much longer than the others. At the end of the 

 last joint are the claws (Fig. 2, kr), of which there are nearly always two. The comparative lengths of 

 the different parts vary, but on the front pair of legs the tibia is generally considerably shorter, and 

 the tarsus longer than the femur ; on the middle pair of legs the three parts are of equal length ; and 

 on the hind pair of legs the femur and the tarsus are of nearly equal length, and the tibia is longer. 

 There are, however, many exceptions to these proportions, and the length of the front tibiae in 

 particular is very variable. The femora are often thickened towards the ends, but rarely exhibit 

 any other peculiarity. The front tibiae have often a narrow linear appendage, varying in length, 

 on the inside, at or above the middle, which stands out more or less (Fig. 27). They have 

 sometimes a claw-like appendage at the extremity also (Fig. 28) called a spine. We generally find 

 two thorn-like appendages called spurs at the extremity of the two hinder pairs of tibiae (Fig. 29, sp), 

 and the hinder tibiae have usually another pair of spines above them, generally just below the 

 middle, but sometimes nearer the joint or the extremity. Their length is different, but the inner 

 ones are always longer than the outer. Many butterflies and Noctnce have one or several rows of fine 

 parallel spines, either on all the tibia; or on the two hinder pairs (Fig. 29). The soles of the tarsi are 

 also frequently furnished with very short and fine bristles, and with longer ones at their extremities. 

 The claws are either simple or finely toothed, and there are sometimes appendages of different 

 forms between them. In other respects the tarsi are always naked, but the femora and tibise are 

 often more or less densely clothed with hair. The hairy covering often forms a kind of tuft or 

 flag on the back of the tibi;e. The front pair of legs are imperfect in many families of butterflies, 

 62 



