160 TEXT-BOOK OF ENTOMOLOGY 



The musculature of the mesothorax and metathorax is similar in those in- 

 sects both of whose pairs of wings are like each other, and act independently 

 during flight, viz. in the Libellulidae. On the other hand, in the second cate- 

 gory, where the fore and hind wings act as a single pair and the fore wings are 

 mostly larger than the hinder (except in most of the Trichoptera), the muscula- 

 ture of the mesothorax is more developed than that of the metathorax. 



To neither category belong the beetles, whose wing-covers are peculiar organs 

 of flight, and not for direct use, and the Diptera, which possess but a single pair 

 of wings. In the beetles the hind wings, in the Diptera the fore wings, serve 

 especially as organs of flight. It may be observed that the Diptera are the best 

 fliers, and that those insects which use both pairs of wings as a single pair fly 

 better than those insects whose two pairs of wings work independently of each 

 other. An exception are the swift-flying Libellulidse, whose specially formed 

 muscles of flight explain their unusual capabilities for flying (Kolbe). 



LITERATURE ON FLIGHT 



Marey, E. J. La machine animale. Locomotion terrestre et aerienne. Paris, 

 1874. 



Me"moire sur le vol des insectes et des oiseaux. (Annal. Scienc. natur., 

 5 s6r., Zool. xii, 1869, pp. 49-150 ; 5 ser., Zool. xv, 1872, 42 Figs.) 



Note sur le vol des insectes. (Compt. rend, et Mem. Soc. d. Biol. Paris, 

 4 ser., v, 1869, C. R. pp. 136-139.) 



Recherches sur le mecanisme du vol des insectes. (Journal de 1'Anatomie 

 et de la Physiologic, 6 Annee, 1869, pp. 19-36, 337-348.) 

 Animal mechanism. New York, 1879, pp. 180-209. 

 Movement. New York, 1895, pp. 239-274. 



Hartings. Ueber den Flug. (Niederland. Archiv f . Zoologie, iv, Leiden, 1877-78. ) 



Lucy. Le vol des oiseaux, chauvesouris et insectes. Paris. 



Tatin, V. Experiences physiologiques et synthe"tiques sur le mecanisme du 



vol. (Ecole prat. d. haut. elud. Physiol. experim. Trav. du laborat. de 



Marey, 1877, pp. 293-302.) 



Experiences sur le vol mecanique. (Ibid., 1876, pp. 87-108.) 



Bellesme, Jousset de. Recherches experimentales sur les fonctions du balancier 



chez les insectes Dipteres, Paris, 1878, 96 pp., Figs. 



Sur une fonction de direction dans le vol des insectes. (Compt. rend., 

 Ixxxix, 1879, pp. 980-983.) 



Pettigrew, J. Bell. On the mechanical appliances by which flight is attained 

 in the animal kingdom. (Trans. Linn. Soc., 1868, xxvi, Pt. I, pp. 197-277, 

 4 PI.) 



On the physiology of wings. (Trans. Roy. Soc. Edinburgh, 1871, xxvi, 



pp. 321-446.) 



Krarup-hansen, C. J. L. Beitrag zu einer Theorie des Fluges der Vogel, Insekten 



und Flederrnause. (Copenhagen u. Leipzig, Fritsch, 1869, 48 pp.) 

 Lendenfeld, R. V. Der Flug der Libellen. (Sitzungsber. d. kais. Akad. d. Wiss. 



Wien, Ixxxiii, 1881, pp. 289-376, 7 Taf. ; Zool. Anz., 1880, pp. 82.) 

 Girard, M. Note sur diverses experiences relatives a la fonction des ailes chez 



les insectes. (Ann. Soc. Ent. France, 4 ser., ii, 1862, pp. 154-162.) 

 Muhlhauser, F. A. Ueber das Fliegen der Insekten. (22. bis 24. , Jahresb. d. 



Pollichia, Diirkheim, 1866, pp. 37-42.) 

 Plateau, F61ix. Recherches expfirimentales sur la position du centre de gravite' 



chez les insectes. (Archiv d. Scienc. phys. et natur. d. Geneve, Nouv. 



pe"riode, xliii, 1872, pp. 5-37.) 



