FIG. 238.—_Vespa crabro_, fixed and stained as in the subjects of the other figures. _I_, _N_, _P_ × 1700; _H_, _J_, _M_ × 850; the others × 425 times: _A-C_, motor muscles of the antennal scape. _D-P_, motor muscles of the 3d coxa. _A_, _B_, the two ends, in very different states of contraction, of the same fibre; on one side the transverse striæ are near together, on the other very far apart. _C_, a crushed and split fibre showing a fibrous appearance, owing to the rupture of the radiated filaments, and the separation of the longitudinal filaments. _D_, muscular disk seen in section, with two rows of nuclei. _E_, a muscular fibre with three rows of nuclei. _F_, a nucleus, accompanied with coagulated protoplasm, oozing from a previous break of the muscular fibre. _G_, nerve-terminations very near each other on the same muscular fibre. _H_, longitudinal filaments, evenly covered with the coagulated substance, and forming, throughout the mass of the fibre, continuous filaments. _I_, filaments widely separated. _J_, longitudinal filaments showing the beginning of one of the transverse breaks which isolate some of the disks. _K_, oblique view of a disk obtained by such a break, and of a fibre in circular section, with an axial row of nuclei; this piece comprises three stages of radiated filaments. _L_, muscular fibre with a row of nuclei; at the lower part, the nuclei have issued from a longitudinal fissure in the fibre, and have remained attached in a chain. _M_, edge of fibre in which there is quite a large, clear space between the sarcolemma and the rods. _N_, passage of the trachea, with the spiral thread, into three capillaries with a smooth cuticula. _O_, elliptical disk from a fibre, with two rows of nuclei, and showing a layer of radiated filaments. _P_, fragment (highly magnified) of the edge of a disk seen in section.—After Janet. ] A humble bee (_Bombus terrestris_) can carry while flying a load 0.63 of its own weight, and a honey bee 0.78; here, as usual, the smaller insect is the stronger.[39] LITERATURE ON THE MUSCLES _a_. General =Lyonet, P.= Traité anatomique de la chenille. La Haye, 1762. =Cornalia, E.= Monographia del Bombyce del gelso. (Mem. R. Instituto Lombardo Sc. Lett. ed Arte, 1856.) =Basch, S.= Skelett und Muskeln des Kopfes von Termes. (Zeitschr. f. wissens. Zool., xv, 1865, pp. 55–75, 1 Taf.) =Lubbock, John.= Arrangement of the cutaneous muscles of the larva of _Pygæra bucephala_. London, 1858. 2 Pls. —— On some points in the anatomy of ants. (Month. Micr. Journ., xviii, pp. 121–142, 1877, 4 Pls.) —— On the anatomy of ants. (Trans. Linn. Soc., Ser. 2; Zool., ii, 1879, pp. 141–154, 2 Pls.)