Ke 
: 
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1884.] Anatomy and Physiology of the Family Nepide. 355 
to differ according to position on the alimentary canal, of which, 
in the Insecta, there are three—on the stomach, biliary alone; on 
the post-ventriculus, urino-biliary ; at the extremity of the alimen- 
tary canal, urinary alone. According to this view they would be 
urino-biliary in the Nepidæ. I am not prepared to speak con- 
cerning their function, as I have made no analysis of their secre- 
tions, 
The Fat Body—The internal organs are entirely enveloped in 
a fatty tissue, called the fat body, which divides the heart and the 
nervous system from the other organs of the body. It is com- 
posed of connective tissue holding in its meshes globules of fat. 
This fat body is always a serious encumbrance in tracing the res- 
piratory system, and it also obscures other internal organs. The 
fat may be dissolved in sulphuric ether, after which the branching 
of the tracheæ may be studied. This tissue is most strongly de- 
veloped in the abdomen, and in the Nepidz I have noticed that it 
is thickest in the fall, and becomes thinner when the insect is de- 
prived of food; it is probably, therefore, a storehouse of nourish- 
ment, and may also serve as a protection to the internal organs. 
The Odoriferous Glands:—In Belostoma, the odoriferous glands 
are two cecal pouches situated in the metathorax, under the 
commencement of the stomach. They are convoluted several 
times upon themselves, and the distal and anterior ends are close 
together, both concealed under the nervous cord; the exter- 
nal opening is between ths coxz of the posterior legs. When 
extended, they will reach to about the fifth abdominal segment. 
The smell emitted by these glands is pleasant, resembling that of 
well ripened pears or bananas, 
The Glands of the Head.—\n the genera, Belostoma, Perthosto- 
ma and Ranatra, I have observed two glands within the head, 
Similar in position to the green glands of the Crustacea, which I 
shall Provisionally name the cephalic glands, since they are not 
mentioned in any authority to which I have access. (Plate 1%, 
à w 2 and 2a.) They are on the floor of the head cavity be- 
eath all the other organs, and therefore are most easily ap- 
ne from beneath. Their external openings are on each 
€ of the head, between the eyes and the base of the beak. The 
are short, and seem to be composed of a number of united 
nee "a originate in individual cells. Under the microscope 
Slands show a thin homogeneous enveloping layer, and an 
ducts, 
