298 . The Brain of the Locust. [ April, 
Fig. 8 a gives an idea of two calices and their mode of attachment 
to the stalk. The peduncle (if we interpret that division of the stalk. 
aright)-sub-divides, sending a thick bundle of fibers to each calyx, 
ending abruptly in the hollow of the calyx. The substance of the 
calices is finely granular, with some coarse granules, and appar- 
ently short scattered irregular fibers. The structure of the calices 
of the locust appears to be more homogeneous than that of the 
cockroach, judging by our sections of the latter. Owing to differ- 
ent treatment by reagents the dark masses described by Newton 
as existing in the cockroach were not so clearly shown in my 
sections (roo inch thick) as in those made by Mr. Newton. The 
substance of the calices when examined under a power of 725. 
diameters is much the same both in the cockroach and the locust, 
the dark bodies not appearing in either. The form of the calices 
is very different in the cockroach, the calices being truly cup-like, 
the disk being deeply folded, and the edges of each cup being 
thin compared with those of the locust. 
The Optic Lobes—As seen in section 19 (PI. 11, Fig. 1 of. 4) 
these bodies are larger than the antennal lobes, and consist of nu- 
merous irregular small bundles of fibers besides those composing 
the optic nerve, the interspaces being filled with fine granular 
nerve substance. The optic nerve is much larger at the outer 
edge of the lobe before passing into the optic ganglion, the fibers 
still being immersed in the finely granular nervous substance. 
The Optic Ganglion —This is situated at the back of the brain, 
and is a large rounded mass of white fine granular nervous mat- 
ter, enveloped in very numerous but small ganglion cells, which 
stain dark red by carmine, the granular matter remaining un- 
stained by the picrocarmine. The granular or white portion is 
subdivided into three rudely lens-shaped masses (see Pl. v, Fig. 1) 
the one nearest the eye being much the largest. 
The Antennal or Olfactory Lobes.—Section 19. (Pl. u1., Fig. 1, 
ant,l.). These are smaller than the optic lobes, though in section 
19 they appear larger. They give rise to the antennal nerve, and 
as the locust carries its ears at the base of the abdomen, the audi- 
tory nérves entering the third thoracic ganglion, reasoning by 
exclusion the antenne in Orthoptera must be organs of smell, 
and the lobes and nerves to the antennz are consequently olfac- 
tory. This is the opinion of some recent writers, notably Hauser. 
' Physiologische und histiologische Untersuchungen tiber das Geruchsorgan der 
Insekten. Siebold und Kélliker’s Zeitschrift fiir Wissen. Zoologie, Bd. 34, Heft. 3- 
