Chap. X.) INSECTS. 381 



CHAPTER X. 



• SECONDARY SEXUAL CHARACTERS OF INSECTS. 



Diversified Structures possessed "by the Males for seizing the Females. — 

 Differences "between the Sexes, of which the Meaning is not under- 

 stood. — Difference in Size between the Sexes. — Thysanura. — Diptera. 

 — Hemiptera. — Homoptera, Musical Powers possessed by the Males 

 alone. — Orthoptera, Musical Instruments of the Males, much diversi- 

 fied in Structure ; Pugnacity ; Colors. — Neuroptera, Sexual Differences 

 in Color. — Hymenoptera, Pugnacity and Colors. — Cojeoptera, Colors ; 

 furnished with Great Horns, apparently as an Ornament; Battles; 

 Stridulating Organs generally common to Both Sexes. 



In the immense class of insects the sexes sometimes 

 differ in their organs for locomotion, and often in their 

 sense-organs, as in the pectinated and beautifully plumose 

 antennae of the males of many species. In one of the 

 Ephemera?, namely Chloeon, the male has great pillared 

 eyes, of which the female is entirely destitute. 1 The ocelli 

 are absent in the females of certain other insects, as in the 

 Mutillida?, which are likewise destitute of wings. But we 

 are chiefly concerned with structures by which one male is 

 enabled to conquer another, either in battle or courtship, 

 through his strength, pugnacity, ornaments, or music. 

 The innumerable contrivances, therefore, by which the 

 male is able to seize the female, may be briefly passed 

 over. Besides the complex structures at the apex of the 



* ! Sir J. Lubbock, ' Transact. Linnean Soc.' vol. xxv. 1866, p. 484. 

 With respect to the Mutillidae see Westwood, l Mod. Class, of Insects,' 

 vol. ii. p. 213. 



