324 PHYSIOLOGY. 



of the male Cicada (Teltigonia, Fab.). In other genera the male is 

 horned, and the female is either wholly unarmed, or its horns are at 

 least much smaller. But the most striking is the sexual difference in 

 Coccus. In this genus the female has the appearance of either a thick 

 conical or flat scale-shaped spot, upon which no external organs are 

 perceived, or at most but the short stumps of feet upon the ventral 

 side. The males, on the contrary, are winged ; they have long dis- 

 tinct antennae and visible legs, but their body is much smaller than 

 that of the female, and in some cases, as in Coccus Adonidis, it is 

 scarcely from the fourth to the eighth part of the size of that of the 

 female. The females, from the abortion of their limbs, have scarcely 

 any motion, whereas the males are exceedingly active, and conse- 

 quently less frequently observed. 



The differences of colour in the two sexes are in harmony also with, 

 and corroborate the assertion of the predominant evolution and involu- 

 tion. The males have brighter, more beautiful, and glittering colours, 

 whereas those of the females are darker, duller, and paler ; or when the 

 colours of the female are brighter than those of the male, for example, 

 in the crepuscular moths and Noctuce, at least the markings of the 

 males are much more distinct, sharper, and clearer. Among the Cole- 

 optera,Harpalus, Amara,o.nA Feronia confirm these observations. Other 

 instances are shown in Tillus elongatus, the prothorax of which is red, 

 whereas the female, or Tillus ambulans, Fab., is entirely black. Some 

 Hymenoptera however form an exception to this rule, for example, the 

 genus Lophyrus, to whose black males we find associated variegated red 

 and brown or yellow and black spotted females ; just so in the genera 

 Tengyra and Myrmosa, their males are uniformly black and the 

 females partially red. Also in the Scolite, the females have generally 

 brighter markings than the males, for example, Scolia horlornm, in 

 which the head of the female is of a reddish yellow; Fabricius conse- 

 quently considered it a distinct species, and called it Sc.flavifrons. 

 In Tiphiafemorata also the male is entirely black, whereas the female 

 has red posterior femorae. But among the butterflies this law receives 

 full confirmation. Many exotic exceedingly splendidly marked males 

 have dirty-coloured insignificant females, for example, the beautiful 

 Papilio Priamus, the female of which is Pap. Panthous ; as also Pap. 

 Helena is the male and Pap. Amphimedon the female of one species ; 

 the same as Pap. Amphrisius is the male, and Pap. Astenous the female. 

 The Pap. Ercchlhcu.s male, and Pap. JEgeus female, described by 



