[54]. See also Giard, Bull. Soc. Ent. France, p. viii, 1894.
[55]. “The contents of the Malpighian tubules may be examined by crushing the part in a drop of dilute acetic acid, or in dilute sulphuric acid (10 per cent). In the first case a cover-slip is placed on the fluid, and the crystals, which consist of oblique rhombohedrons or derived forms, are usually at once apparent. If sulphuric acid is used, the fluid must be allowed to evaporate. In this case they are much more elongated, and usually clustered. The murexide reaction does not give satisfactory indications with the tubules of the cockroach.” (Miall and Denny, The cockroach, p. 129, footnote.)
[56]. “There is a curious analogy between the excretory organs of these insects and the mesonephros of some vertebrates, where a second, third, etc., generation of tubules is added to the primitive metameric series. When the embryonic number of Malpighian vessels persists in insects, the demand for greater excreting surface is supplied by a lengthening of the individual vessels.”
[57]. For the mode of adhesion of Cynips eggs, see Adler in Deutsche Ent. Zeits. 1877, p. 320.
[58]. Mercaptan is a mercury, belonging to a class of compounds analogous to alcohol, having an offensive garlic odor. Methyl mercaptan is a highly offensive and volatile liquid.
[59]. Embryonic or temporary glands, the “pleuropodia” of Wheeler, viz. the modified first pair of abdominal legs, occur in Œcanthus, Gryllotalpa, Xiphidium, Stenobothrus, Mantis (occasionally a pair on the second abdominal segment, Graber); Blatta, Periplaneta, Cicada, Zaitha, Hydrophilus, Acilius, Melolontha, Meloë, Sialis, Neophylax. (See Wheeler, Appendages of the First Abdominal Segment, etc., 1890.)
[60]. These midges owe their phosphorescence to bacteria in their bodies during disease.
[61]. Untersuchungen zur Anatomie und Histologie der Tiere, 1884, p. 72.
[62]. Zelle und Gewebe, 1885, p. 43. (See also our p. 217.)
[63]. Studien über die Lampyriden, Zeits. für wiss. Zool., xxxvii, 1882. Both Wielowiejski and M. Wistinghausen have completely disproved the view of Schultze, that the tracheæ end in star-like cells, where respiration takes place, as the “star-like cells” are simply net-like expansions of the peritoneal membrane of the tracheæ.