1 1 6 A nnals Entomological Society of A merica [Vol . I , 



From the large size of the terminal ganglion and because of 

 the numerous nerves arising therefrom, it is evident that it is pro- 

 duced by the fusion of two or more ganglia. Oudemans '87 

 determined in Machilis maritima Latr. that the last abdominal 

 ganglion originated by the fusion of the last three ganglia. On its 

 dorsal side there remained parts of two transverse nerves, which 

 indicated the boundaries of the original ganglia. Such rudiments 

 of the transverse nerves have not been found in the terminal 

 ganglion of the Corydalis larva. Influenced, however, by the fact 

 that there are four pairs of nerves arising from this ganglion, w^e 

 may conclude that these correspond to two lateral and two ventral 

 pairs of nerves of two abdominal ganglia. Although it may be 

 possible to homologize some of these nerves with those of previous 

 ganglia, it cannot be considered conclusive that the last ganglion 

 is produced by the fusion of but two ganglia, since it may be pos- 

 sible that the nerves corresponding to a third have disappeared. 

 An investigation of the embryological condition would be the 

 only way to settle this problem. 



Notwithstanding the cephalic displacement of the eighth gan- 

 glion, all of its nerves innervate the eighth and terminal segments. 

 As stated above, there are four pairs of nerves arising from this 

 ganglion (Fig. 10 a, b, c, d). The first of these originates from 

 the lateral border of the ganglion and runs caudo-laterad to 

 various parts of the eighth segment. The branches of this nerve 

 can readily be homologized with the lateral nerve of previous 

 ganglia. Branch i, as in some of the previous ganglia, is in this 

 case absent altogether. Branch 2 passes over the large ventral 

 muscle bundle m^ in the eighth segment and innervates the ventral 

 muscles. Branch j supplies the dorsal parts of the segment; 

 branch 4 enters the lateral filament; branch 5 joins the tracheal 

 nerve. 



Nerve b is homologous with nerve v of the previous segment. 

 It originates from the mid- ventral portion of the ganglion and 

 extends caudad, passing underneath the ventral muscles (nis), 

 then turning laterad, innervating approximately the same regions 

 as the ventral nerve of previous ganglia. 



Very probably nerves c and d are homologous to the lateral (/) 

 and ^^entral (v) nerve trunks of ganglion 7. Nerve c has three 

 prominent branches, the first of which forks giving off one nerve 

 to the lateral filament and one to the proleg. Branch 2 enters 

 the proleg. Branch j innervates the reproductive organs as 



