46 



The Larva of Cliirononius 



the ganglia in front or behind ; and at the junction 

 of the median and transverse nerves there is a minute 

 triangular plexus. The first, second, third, and tenth 

 transverse nerves are thus connected with the thoracic 

 ganglia in front of them, while the fourth to the ninth 

 inclusive join the second to the seventh abdominal 



ganglia behind. The origin 

 of the tenth and last trans- 

 verse nerve lies immediately 

 above the eighth abdominal 

 ganglion, and its median nerve 

 is too short for observation. 

 The first abdominal ganglion 

 has no transverse nerve, owing 

 to the concentration of the 

 ganglia in this region, where 

 there is more than one gan- 

 glion to a segment. Each 

 transverse nerve lies along 

 the junction of two segments, 

 and the figures show that every 

 junction between the prothorax 

 and the eighth abdominal seg- 

 ment has its nerve. The third 

 and tenth transverse nerves 

 take an oblique course owing to the forward displace- 

 ment of the ganglia from which they spring. 



Similar nerves have been elaborately figured and de- 

 scribed byLyonet^ in the caterpillar of Co5SM5 lign'qjerda; 

 by Newport- in the caterpillar of Sphinx ligustri; hy 

 Leydig '^ in Locusta inridisslma ; they have also been 

 found in various other insects'*. Lyonet gives no 



Fio. 37. — Thoracic ganglia and 

 transverse nerves of larva, the 

 latter in black. Letters as in 

 <ig. 35. t.mitfi, transverse muscle. 



' Traiti anakiniiquc, p. 2or, pi. ix, fig. i. '^ 1834, p. 401, pi. xvi. 



' 1864 a, pi. vi, fig. 3. See also Leydig, 1864 b, p. 203. 

 * Ann. Sci. Nat.; Zool., x, pp. 5-10 (1858). 



