Larva of Privet Hawk Moth. 85 



by a single oval foramen, the third post-oral ganglion having dis- 

 appeared, and the mass made up by the fusion of the fourth and 

 fifth, having closely approximated to that representing the second. 



For a detailed account of the metamorphoses of the nervous system 

 in the Sphinx Ligustri, resulting in the replacement of the 

 eleven ventral ganglia of the larva by one sub-oesophageal, 

 two thoracic and four abdominal in the imago, see Newport, 

 Phil. Trans., 1833 and 1834; or. Cyclopaedia of Anatomy and 

 Physiology, Article ' Insecta,' p. 962 ; Herold, ' Entwickelungs- 

 geschichte der Schmetterlinge,^ pp. 58, 59 ; and description 

 of Tab. ii., where he speaks of the ventral ganglia of the larva 

 of Papilio Brassicae as being twelve in number ; the com- 

 missural cords between the eleventh and twelfth being absent. 



For accounts of the first appearance of the nerve system, in the 

 developing embryo of various orders of insects, see Weismann, 

 ' Entwickelung der Dipteren,^ 1864, pp. 38, 82, 190, 193; 

 Rathke, ' Zur Morpliologie, Reisebemerkungen aus Taurien,^ 

 1837, pp. 123-137; Leon Dufour, Ann. Sci. Nat., Ser. ii. 

 tom 18, pi. iv. and v. See also, for the relatively late period 

 at which the nerve system is developed and differentiated from 

 the structures which underlie it, E-athke, ' Bildung und Ent- 

 wickelung des Flusskrebses,^ p. 85 ; Zaddach, ' Die Entwicke- 

 lung und den Bau der Gliederthiere/ 



For development of the first sub-oesophageal ganglion, see Metschni- 

 kow, ' Embryologische Studien an Insecten,^ p. 79, Taf. xxx., 

 fig. 33; Zeitschrift fiir Wissenschaftliche Zoologie, Bd. xvi. 



For the ^nervi transversi,^ see Newport, 1. c. 1834, p. 401 ; Ley dig, 

 Vergleich Anat. p. 205, Taf. vii. fig", i, Taf. ix. fig. 2. 



For descriptions and figures of the systems of tracheae and of 

 muscles, see Lyonet, Traite Anatomique de la Chenille qui 

 ronge le bois de Saule, 1762; and Newport, Phil. Trans. 

 1836 ; and for descriptions of the variations in the muscles of 

 the larva of Pygaera Bucephala, see Lubbock, Linn. Soc. 

 Trans., vol. xxii. pt. iii., 1857. 



For the relations existing between the external and internal struc- 

 tures, see Burmeister's ' Manual of Entomology,' translated by 

 W. E. Shuckard, p. 281 ; Blanchard, Ann. Sci. Nat., Ser. iii., 

 tom. v., 1846, p. 281. 



