HAA C. GORDON HEWITT. 
of the stalks of the prothoracic and ventral mesothoracic imaginal dises. 
c.l. Cerebrallobe. ¢.r, Problematical cellular structure (Weismann’s ‘ring ”). 
d.a'., d.a'’., d.a’”’, Dorsal accessory nerves. d.v. Dorsal vessel. m.c.d. 
Major cephalic imaginal dises. @. Gisophagus. pr.d. Prothoracic imaginal 
disc. ¢. Fine trachese which arise in association with the sezmental nerves, 
others arise with some of the more posterior nerves, but for the sake of clear- 
ness they are not included in the figure. ¢7’., ¢v’’”. Trachew entering the gan- 
glion. v.m.s. Ventral mesothoracic imaginal disc. v.. Visceral nerve. 
Ire, 25.—Longitudinal section of the proventriculus of the mature larva 
(Camera lucida drawing.) 
c.c. Large cells forming the central hollow core of the proventriculus, ch.7. 
Chitinous intima of the cesophagus. e.v. Epithelial cells continuous with and 
similar in character to those of the ventriculus. 7.c, Ring of imaginal cells. 
a@.ep. (Msophageal epithelial cells. v.c. Lumen of ventriculus, 
Fie. 26.—The longitudinal lateral tracheal trunk of the left side seen latero- 
dorsally showing the origin of the tracheal branches ; small portions only of 
the right trunk are shown. 
a.com. Anterior tracheal commissure. a.sp. Anterior spiracular process. 
Sb. Bat-body. ord. Oral lobe. 7.¢r. Longitudinal lateral tracheal trunk. 
p.com. Posterior commissure. p.sp. Posterior spiracle. ¢7’. Trachea entering 
ganglion anteriorly. dé”. Trachea entering ganglion laterally. v.¢r. Visceral 
tracheal trunk, 
Fic. 27.—Longitudinal sections through the major cephalic imaginal dises 
of mature larva to show the position of the individual imaginal rudiments. The 
dextral section is more dorsal than the sinistral. (Camera lucida drawings.) 
an.d. Imaginal dise of the antenna. fd. Facial imaginal dise. ¢.s, Sheath 
of imaginal rudiments. 0.d. Optic imaginal disc. o0.g. Imaginal dise of the 
optic ganglionic structures, 0.8. Optic stalks. s.g. Fundament of the 
imaginal supra-cesophageal ganglionic. sf. Sheath of cerebral lobe. 
V'1c. 28.—Transverse section of mature larva anterior to the ganelion and 
cerebral lobes to show the position of certain of the imaginal discs. The body- 
wall and muscles have been omitted. The folded character of the adipose 
tissue laminge can be seen in this section, and also the degenerating anterior 
portions of the malpighian tubules (m.¢.). (Camera lucida drawing.) 
aun.d. Antennal disc. ¢.7. Problematical cellular structure (Weismann’s 
‘“‘ring”’), ev. Caecum of ventriculus. d.ms. Dorsal mesothoracic (alar) 
imaginal disc. 1c. Adipose tissue cell. /.¢r. Lateral tracheal trunk. m.t, 
Malpighian tubule cut rather longitudinally. @. Cisophagus. pr.d. Pro- 
thoracic imaginal dise. v.ms, Ventral mesothoracic imaginal dise. 
