514 PSYCHOLOGICAL PHYSIOLOGY. 



longer. Hence copulation is the object for which Nature produces 

 individuals, and she must necessarily be anxious for its most easy and 

 securest attainment. We find several arrangements to promote this 

 object, which facilitate the mutual meeting of the sexes,, some of which 

 are merely corporeal, and others are called forth by the instinct. In 

 the majority of cases it is in the male that this impulse first becomes 

 active, and it is therefore they especially which seek the female. When 

 difficulty attends this, Nature has often provided peculiar organs to 

 render it more easy. One of the most usual means consists in the 

 males being more numerous than the females ; indeed it is not possible 

 to give the exact proportions of the sexes, but it is, according to 

 De Geer's calculation, among the Phalence, about three to one; or, 

 according to Lyonet, about four to one. Among the bees there are 

 several hundred males and only one fertile female. Another means is 

 the greater activity of the male. They are generally smaller in size, 

 have longer wings, longer antennae and legs, or have wings in many 

 instances when the female is without them, as in Lampyris, Symbius, 

 Psyche, many Phalence (Acidalia brumata, &c.), the Mutillee, Methoca, 

 Myrmosa, &c. Sometimes, also, the females have peculiar marks of 

 distinction, as in Lampyris, in the female of which the light emitted 

 is considerably brighter than that produced by the male. A reversed 

 relation occurs in the Achetce, Locustce, and Cicada, in which the 

 males are furnished with a vocal organ not found in the females. We 

 observe the same phenomena also in the singing birds, among which 

 the males only are the songsters. Thus Nature wished, by furnishing 

 the males with distinguishing characters, to place them in a condition 

 to lure the females from their hiding places, which in most of the men- 

 tioned instances it is their habit to resort to. Others, as the nocturnal 

 Lepidoptera, have received for this purpose a very developed sense of 

 smell, by means of which they can discover the female at considerable 

 distances, to whom they immediately flock. I have myself observed 

 males of Liparis salicis fluttering around my breeding-cage, in which 

 there were several just developed females of the same species ; upon 

 my letting them into the cage they immediately copulated. This 

 instinctive impulse, the satisfying of which nature has thus faci- 

 litated, is most conspicuous also in the Lepidoptera. The males of 

 many Noctuce will even copulate with impaled and half dead females, 

 and the excitement of other insects occasionally urges them to an inter- 

 mixture with individuals of a different species, and even of a different 



