24 WILLIAM T. M. FORBES 



the tibia. The hind tibiae have a second pair, usually near or below 

 the middle. 



In many butterflies and Noctuidae the tibiae bear spines similar to 

 those on the tarsus, but less regularly arranged. Males frequently 

 have tufts of sex-hairs, and in many cases the tibia is grooved to pro- 

 tect them. On the hind legs of many Ennomid geometers, the tibia 

 is largely hollow and the tuft almost completely enclosed, though its 

 point of attachment is regularly on the exterior. 



The last five segments constitute the tarsus, or foot, the most basal 

 being the metatarsus. This segment is usually much larger than the 

 other four, and occasionally bears special tufts or spines. The final 

 segment (fig. 18) ends in two articulated and curved claws, and an 

 adhesive pad between them, the pulvillus. On the inner side of each 

 claw, toward the pulvillus, there is often a sensory membrane, the 

 paronychium. These are large and conspicuous in the Sphingidae, and 

 are often forked. The pulvillus is rarely minute or absent. 



The tarsal segments are also armed with smaller spines, which 

 usually form three or four rows on the ventral surface, but sometimes 

 are dorsal also, or gathered into tufts at the tips of the segments. They 

 are sometimes concealed in the scaling, though rarely absent. Often 

 they are wanting on the base of the metatarsus and are differently 

 arranged on the last segment. In the family Nymphalidae, the fore 

 legs are reduced and not used for walking. They have no claws and 

 the segments are more or less fused, but the general appearance of a 

 leg is retained. The male carries the reduction slightly further than 

 the female. The Erycinidae and Libytheinas show less reduction in the 

 male and none in the female: in their males the tarsus is very small 

 and without claws, and the tibia extends beyond its insertion as a sort 

 of claw. In the males of the Lycasnidae the fore legs are still less 

 reduced; while the leg has lost its claws, it is functional, ending either 

 in a single claw-like spine or a group of spines. In the Hermimin 

 the leg is more curiously modified in the male, although perfectly nor- 

 mal in the female. The coxa may be very long and movable (it is never 

 as closely fused with the body in the fore leg as in the middle and hind 

 ones). The trochanter is sometimes lengthened. The femur tends to 

 be weak, the tibia and first joint of the tarsus, either or both, may be 

 hollowed out to a mere shell, enclosing enormous tufts of hair; and 

 the tarsus is sometimes minute. The leg as a whole may be enlarged 

 or reduced. Many moths, especially geometers, bear a tuft of fine hair 

 at the junction of the hind tibia and femur, or on the tibia near the 

 base; this is also often contained in a hollow in the tibia, and in some 

 cases is lost at copulation. In the Acidaliinae the tibia may be much 

 enlarged to enclose it, or may be reduced, even to an extreme, while 



