[429] ‘The Practical Entomologist,’ Philadelphia, vol. ii. May, 1867, p. 88.
[430] Mr. Walsh, ibid. p. 107.
[431] ‘Modern Classification of Insects,’ vol. ii. 1840, p. 206, 205. Mr. Walsh, who called my attention to this double use of the jaws, says that he has repeatedly observed this fact.
[432] We have here a curious and inexplicable case of dimorphism, for some of the females of four European species of Dytiscus, and of certain species of Hydroporus, have their elytra smooth; and no intermediate gradations between sulcated or punctured and quite smooth elytra have been observed. See Dr. H. Schaum, as quoted in the ‘Zoologist,’ vol. v.-vi. 1847-48, p. 1896. Also Kirby and Spence, ‘Introduction to Entomology,’ vol. iii. 1826, p. 305.
[433] Westwood, ‘Modern Class.’ vol. ii. p. 193. The following statement about Penthe, and others in inverted commas, are taken from Mr. Walsh, ‘Practical Entomologist,’ Philadelphia, vol. ii. p. 88.
[434] Kirby and Spence, ‘Introduct.’ &c., vol. iii. p. 332-336.
[435] ‘Insecta Maderensia,’ 1854, p. 20.
[436] E. Doubleday, ‘Annals and Mag. of Nat. Hist.’ vol. i. 1848, p. 379. I may add that the wings in certain Hymenoptera (see Shuckard, 'Fossorial Hymenop.’ 1837, p. 39-43) differ in neuration according to sex.
[437] H. W. Bates, in ‘Journal of Proc. Linn. Soc.’ vol. vi. 1862, p. 74. Mr. Wonfor’s observations are quoted in ‘Popular Science Review,’ 1868, p. 343.
[438] Kirby and Spence, ‘Introduction to Entomology,’ vol. iii. p. 299.