SENSE ORGANS OF THE LOCUST. 
189 
much as this layer is homologous with the epidermis of other animals, 
it seems desirable to secure uniformity of nomenclature by adopting this 
name for the subcuticular layer of cells. I have not devoted much at- 
tention to this tissue. Its relations and proportionate size in locusts to 
the cuticula, Cu., can be seen at Ep., in Fig. 7. The cells composing it 
are cylindrical and form but a single layer, interspersed through which 
are numerous hair cells, as above described. 
In Anabrus, the epidermis is composed of high cylinder-cells, which 
contain a great deal of granular pigment, often sufficient to completely 
hide the nucleus. „ Seen from the surface these cells present polygonal 
outlines (Fig. 5G). When in such a view the nucleus is visible, the 
character of the cuticular matrix is at once evident, and it becomes certain 
that Leydig was entirely wrong in his assertion that the " hypodermis " 
of insects is formed by connective tissue and not by an epithelium. This 
mistake has already been carefully and accurately pointed out by 
Graber. 231 
The coloration of Anabrus depends principally upon the pigment of 
the epidermis shining through the cuticula. Most of the cells contain 
dull reddish-brown granules, but scattered in among them are patches 
of cells blight green in color. I have observed no cells intermediate 
in color ; on the contrary the passage is abrupt, a brown or red cell lying 
next a green one. Indeed I have never seen any microscopic object 
more bizarre than a piece of the epidermis of Anabrus spread out and 
viewed from the surface. My thought upon first seeing such a prepara- 
tion was that my reagents must have played me some trick, but prepa- 
rations made from alcoholic specimens, and examined in alcohol, without 
having been exposed, to my knowledge, to any other reagent, exhibited 
the same peculiarities. 
The student will find observations on the coloration of the epidermis 
and cuticula of insects in an article by Dr. Hagen, 232 and a memoir by 
Leydig. 233 
Sense organs. — This would be the proper place to describe the sense 
organs, the eyes, and auditory apparatus, &c, but the extreme difficulty 
of preparing these organs satisfactorily induced me to neglect them 
entirely, in order to devote my whole time to the investigation of other 
points, concerning which results were more readily attainable. For the 
convenience of those who may wish to know the present state of our 
knowledge concerning these obscure structures, I quote below the titles 
of some of the more important recent papers, 234 especially those which 
give references to the earlier publications. 
01 Graber: Denkschr. Wien. Akad. wiss. Bd. xxxvi. (1876), p. 33. 
231 Hagen: American Naturalist, vol. vi, p. 388. 
^Leydig: Bemerknngen Uber die Farbon der Hantdecke, etc., bei Insekten. A. f. m. A., Bd. xiii, 8. 
536 (1876). 
^Leydig: Geruchs-uud G-ehororgan der Krebse and Tnsekten. Muller's Archiv., 1860, p. 292. 
Wolf: Das Riechorgan der Biene. Nova. Acta, xxxviii., No. 1. 
Orobben : Ueber Blaschenformige Sinnesorgane der Larve von Ptychoptera contaminata. Sitzbor. 
Wien. Akad.. Bd. lrxii. (1876). (List oontinned on next page.) 
