The Structure and Special Physiology of Insects 21 
in the paired arrangement of the spiracles and tracheal trunks leading from 
them, a segmental condition is obvious. The central nervous system consists 
Fig. 41. —Larva of giant crane-fly, Holorusia rubiginosa. A, entire; B, dissected, show¬ 
ing all organs except the muscles and ventral nerve-chain, h., head; ant., antenna; 
i.b.res., imaginal bud of pupal respiratory tube; i.b.wg., imaginal bud of wing; 
i.b.ms.l., imaginal bud of mesothoracic leg; i.b.h., imaginal bud of balancer; 
i.b.mt.l. , imaginal bud of metathoracic leg (the imaginal buds of fore legs are con¬ 
cealed by head-capsule); sal.gl., salivary gland (the other salivary gland is removed); 
br., brain; oes., oesophagus; prov., proventriculus; susp., suspensorium; g.c ., gastric 
coecum; vent., ventriculus; tr., trachea; ad.tis., adipose tissue; mal.tub., Malpi¬ 
ghian tubule; d.v., dorsal vessel; w.m., wing-muscles of pericardium; sm.int., 
small intestine; tes., testis; int.c., intestinal caecum; v.d., vas deferens; Lint., large 
intestine; sp., spiracle; term.pr., terminal processes. (Twice natural size.) 
of a brain and a ventral chain of pairs of ganglia segmentally arranged and 
connected by a pair of longitudinal cords or commissures (Figs. 42, 43, 44). 
The two members of each of the pairs of ganglia as well as of the pair of 
