[66] J. S. Kingsley in Q. J. Micr. Sci. (1885), has reviewed the homology of Insect, Arachnid, and Crustacean appendages, and comes to conclusions very different from those hitherto accepted. He classifies the appendages as pre-oral (Insect-antennæ) and post-oral, and makes the following comparisons:—
| Hexapoda. | Acerata. | Crustacea. |
| (=Insecta + Myriopoda?) | (=Arachnida + Limulus.) | |
| (1) Antennæ. | Absent. | Absent. |
| (2) Mandibles. | Cheliceræ. | Antennules. |
| (3) Maxillæ. | Pedipalpi. | Antennæ. |
| (4) Labium. | 1st pair legs. | Mandibles. |
| (5) 1st pair legs. | 2nd pair legs. | 1st Maxillæ. |
| (6) 2nd pair legs. | 3rd pair legs. | 2nd Maxillæ. |
| (7) 3rd pair legs. | 4th pair legs. | 1st Maxillipeds. |
Pelseneer (Q. J. Micr. Sci., 1885), concludes that both pairs of antennæ are post-oral in Apus, and probably in all other Crustacea.
[67] Many Orthoptera, which seize their prey with the fore legs, have a very long pronotum.
[68] Also in Phasmidæ (see Scudder, Psyche, Vol. I., p. 137).
[69] Professor Huxley (Anat. Invert. Animals, p. 404) points out that the so-called pulvillus ought to be counted as a sixth joint. The same is true of the foot of Diptera and Hymenoptera, where there are six tarsal joints, the last carrying the claws. (Tuffen West on the Foot of the Fly. Linn. Trans., Vol. XXIII.)
[70] The nomenclature adopted by Packard (Third Report of U.S. Entomological Commission) seems to us open to theoretical objections.
[71] On wing-plaiting and wing-folding in Blattariæ see Saussure, Etudes sur l’aile des Orthoptères. Ann. Sci. Nat., Sér. 5e (Zool.), Tom. X.
[72] Grundzüge der Vergl. Anat. (Arthropoden, Athmungsorgane.)
[73] Origin and Metamorphoses of Insects, p. 73.