[55]

Var. under Nature & Transition

Discuss Dimorphism as in 4th edit of Origin — Whether wingless Bugs — Dytiscus with sulcæ —Pascoes male Beetle Lucanus with Horns, (but have them in transition?) Sir Andrew Smith & azaras case of Broods of 2 sizes without transitions are cases of abrupt var. with no blending viz crossing — or Dimorphism or var. of →

[55v]

Sexual characters, not yet Known — Here allude to "summer & autumn Broods of moths" — Wallace but this may be case of Phytophagic variation —

[Origin 4th ed., p. 50: "Individuals of the same species often present great differences of structure, not directly connected with variability, as in the two sexes, as in the two or three castes of sterile females or workers amongst insects, and as in the immature and larval states of all animals. There are, however, other cases, namely of dimorphism and trimorphism, which might easily be, and have frequently been, confounded with variability, but which are really quite distinct. I refer to the two or three distinct forms, which certain animals of either sex, and certain hermaphrodite plants, habitually present. Thus, Mr. Wallace, who has lately called special attention to the subject, has shown that the females of certain species of butterflies, in the Malayan archipelago, regularly appear under two or even three conspicuously distinct forms, not connected together by intermediate varieties. The winged and frequently wingless states of so many Hemipterous insects may probably be included as a case of dimorphism, and not of mere variability."]