[64]. The following summary compiled from Krancher, is translated, with some minor changes, from Kolbe’s work.
[65]. Miall and Denny state that in the cockroach the abdominal spiracles are permanently open, owing to the absence of a valve, but communication with the tracheal trunk may be cut off at pleasure by an internal occluding apparatus.
[66]. Zur Entwicklungsgeschichte der Biene, Zeitschr. wissens. Zoologie, xx, p. 519, 1870.
[67]. Die Entwicklung der Dipteren im Ei, Zeitschr. wissens. Zoologie, xiii, 1863.
[68]. Amer. Naturalist, May, 1886, p. 438.
[69]. Zeitschr. wissens. Zoologie, xl, 1884, Taf. xix, Fig. 8, T.
[70]. Science, 1893, pp. 44–46.
[71]. Art. Thorax, Todd’s Cycl. of Anat. and Phys.
[72]. The mesothoracic stigmata are open in Carabus, Potamophilus, Elmis, Macronychus, Buprestis, Elater, Lampyris, Lycus, Triphyllus, Eucinetus, Dascillus, Psephenus, Ergates, Micralymna, and probably many others. The metathoracic stigmata are open in Lycus and Elmis.
[73]. In the Hymenoptera the two pairs on the meso- and metathoracic segments are open in the Aculeata, also in the Siricidæ, among which sometimes that on the third segment is closed. In Pimpla and Microgaster (fully grown larvæ) only the mesothoracic stigmata are open.