[56] The reader who desires to follow this subject further is recommended to study chap. vi. of Graber’s Insekten, which we have found very useful.
[57] Freshwater Crustacea, however, are sometimes similar to their parents at the time of hatching.
[58] In Dytiscus the mandibles are perforate at the base, and not at the tip. See Burgess in Proc. Bost. Soc. Nat. Hist., Vol. XXI., p. 223.
[59] Ein Käfer mit Schmetterlingsrüssel, Kosmos, Bd. VI. We take this reference from Hermann Müller’s Fertilisation of Flowers.
[60] An interesting account of the structure and mode of action of the Bee’s tongue is to be found in Hermann Müller’s Fertilisation of Flowers, where also the evolution of the parts is traced through a series of graduated types.
[61] See Newport’s figure of Vanessa atalanta (Todd’s Cyc., Art. Insecta), or Burgess on the Anatomy of the Milk-weed Butterfly, in Anniversary Mem. of Boston Soc. Nat. Hist., pl. ii., figs. 8–10 (1880).
[62] Balfour, Embryology, Vol. I., p. 337.
[63] Huxley, Med. Times and Gazette, 1856–7; Linn. Trans., Vol. XXII., p. 221, and pl. 38 (1858).
[64] “I think it is probable that these cervical sclerites represent the hindermost of the cephalic somites, while the band with which the maxillæ are united, and the genæ, are all that is left of the sides and roof of the first maxillary and the mandibular somites.”—Huxley, Anat. Invert. Animals, p. 403.
[65] Balfour, Embryology, Vol. I., note to p. 337.