[380] PLATE XVIII. FIG. 1. as to the thoracic shield.
[381] _May_ 27, 1822. This day, T. Allen, Esq. F.L.S. brought me in a phial a vast number of the little insect which Goedart, Frisch, and De Geer took for the larva of _Meloe Proscarabæus_, which he found on the leaves of _Achillea Millefolium_. These little animals were coursing each other with wonderful velocity over the sides of the phial. To assist them in their motions, they applied to the surface of the glass the end of their abdomen, using it, like many larvæ of _Coleoptera_, as a seventh leg. This circumstance excited a suspicion in the minds of both Mr. MacLeay sen., then visiting me, and myself, that after all they might be _coleopterous_ larvæ. One, amongst other circumstances, however, seemed to militate strongly against this opinion; namely, that in this infinite number none appeared to differ in _size_.
[383] Ibid. FIG. 12.; PLATE XVIII. FIG. 4, 11, 13, &c.
[386] _Ibid._ FIG. 3. Reaum. v. 97. _t._ xii. _f._ 17, 18.; De Geer ii. 1004. _t._ xxviii. _f._ 12.
[394] Ibid. _t._ xiii. _f._ 16-19. A very singular larva, which preys upon that of _Aleyrodes proletella_ Latr., if Reaumur's figure be correct (ii. _t._ xxv. _f._ 18-20), is of a perfect _Chilopodiform_ type, the abdominal legs being represented by a tubercle crowned by a bristle: yet even this, which turns to a minute beetle (Ibid. _f._ 21), has some tendency to the _Anopluriform_ type.
[395] "Squilla _insectum a_ squilla _pisce parum differt_." Mouffet, 319.
[396] A remarkable difference obtains between the larva of the wire-worm and that of _Elater undulatus_. In the former, the last segment is longer than the preceding one, terminating in a small acute mucro at the apex, with a deep cavity, perhaps a spiracle, on each side, at the base. In the latter, this segment is shorter than the preceding one, forming above a nearly circular plate; the margin of which is a little elevated, and armed on each side with three teeth, and at the apex with a pair of furcate recurved horns, and without any basal spiracle. De Geer iv. 156. _t._ v. _f._ 25. I have a similar larva, but not the same species.
[400] _Traité Element._ ii. 35. _n._ 577.
[401] _Trans. Linn. Soc._ vii. 66. _t._ vi. _f._ 3.