1 8 PROCEEDINGS OF THE 



condition presented b}' so many females is associated with their 

 other habits of concealing themselves when burdened with eggs or 

 engaged in laying them ; of these we have examples in Nyssia 

 hispidaria amongst Lepidoptera, various species of Mutilla in 

 Hymenoptera, and our common black-beetle amongst Orthoptera. 

 The wings of certain Lepidoptera are also sometimes distin- 

 guished by special lobes, as Lohophora hexapterata ; perhaps the 

 most extreme difference is found as regards the wings in that 

 remarkable group of highly modified beetles belonging to the 

 genus Sti/lops, in which the female is a limbless grub-like 

 creature parasitic in the abdomen of bees, whereas the male is 

 an active large-winged insect. 



As regards sound-producing organs in this group, if it be con- 

 fined to one sex, it is the male which possesses them, as in 

 Cicadse, Acridae, &c. 



Turning now to the Vertebrata, in fish it is almost invariable 

 that the male is more conspicuous from brilliant coloration, the 

 colours being intensified at the breeding-season. The genus 

 Girardiiius illustrates this very well. Special skin-appendages 

 are found distinguishing by their presence the males from the 

 females, as the warts on the head of the male of Discognathus 

 and the special process on the head of the male of Chimcera. It 

 is suggestive that the young of Myxine fjlutinosa is a male until 

 it has attained a length of 32-33 centimeti^es, and then assumi^s 

 the female state. In Glirysoplirys auratus the same individual is 

 stated to become male or female at difi'erent times of the year. 

 Not only do the males diff"er from the females by such integu- 

 mentary warts mentioned in Discognathus, but the teeth, which 

 are essentially of dermal origin, sometimes present marked dif- 

 ferences in the sexes, as in Raia clavata, in which the ma It- 

 has pointed teeth, whereas the female teeth are rounded fur 

 crushing. 



In Amphibia the male Triton at the breeding-season shows tlu' 

 well-known immensely developed crest of skin, with the broi.d 

 swimming tail and the brilliant coloration, features which disti;;- 

 guish it from the simpler adornment of the female. "We havi 

 also the gular pouches so well developed in the male Eana escii- 

 lenta, the glandular patch on the fore limbs of Pelohates, th^- 

 immensely distensible subgular pouch of .HyZ« arhorea, but ii 

 most Anura the male is smaller than the female. In lizards ti ■ 

 male is commonly the larger, brilliantly coloured, and more con- 

 spicuous than the female, as we see in Calotes nigrilahris & . 

 Amongst Bats secondary sexual characters are well known, as i ■ 

 the special supranasal appendages of Phyllorhina, the gular pou' i 

 of TapJiozous longimanus, the special gular hairs of T. melanu- 

 pogon, the special tuft of coloured hairs with associated gland on 

 the shoulder oi Epomopliorus, or the curious sac on the win_ o. 

 Saccopteryx. 



In Mammals the familiar crest or distensible chamber on th 



