70 Psyche [April 
The salivary glands are highly developed and differ somewhat in 
the nymph and adult. The great length of coiled, chitinous duct 
situated entirely within the upper part of the head acts, I believe, 
as a salivary-reservoir. At its distal end is a small and irregularly 
shaped flattened gland, also within the head. Eleven of the tubular 
glands reach, when straightened out, beyond the end of the abdo- 
men, and, therefore, are somewhat serpentine within the body, or 
their ends are recurved and lie at the posterior end of the abdomen 
amongst the fat-body and other organs. The twelfth tube is 
shorter and thicker and lies partly within the head,being apparently 
entangled and drawn in by the coil of salivary-reservoir and muscles 
of the head. The anterior lobes of the glands lie within the pro- 
and meso-thorax. The secretion of the glands seems to be neutral 
or very faintly alkaline. 
In the nymph of the Cercopid there is a curious arrangement of 
the spiracles, primarily, no doubt, for the purpose of preventing 
them from becoming choked with the glutinous froth or spume 
in which the nymph lives. The tergal plates and pleura of the 
abdomen are greatly produced and bent around the underside of 
the abdomen till the opposing ends touch one another. Thus is 
formed—for the whole length of the abdomen—on the underside 
of the nymph a large air-chamber or reservoir. The spiracles 
open into the upper part of this chamber, so that although the 
whole chamber and spiracles are, of course, integumentary and 
external, nothing can be seen of them by viewing the nymph on the 
exterior, unless the ends of the plates closing the chamber are 
turned up. Apparently the whole sternal surface of the abdomen 
has been invaginated and has thus drawn inwards the pleural region 
with the spiracles, and pulled around the ends of the tergal plates, 
as shown in the diagrammatic sketch. In the adult the tergal and 
sternal plates with the pleura have returned to a normal position, 
and consequently there is no air-reservoir. The nymph appears 
to hermetically seal itself with the froth, but the amount of air 
contained in the chamber is sufficient to last for a considerable 
time. I think, however, that from time to time the nymph breaks 
through the covering of froth—generally with one of the fore legs 
—and thus admits a fresh supply of air, afterwards resealing the 
rent with fresh mucinoid. At each moult, also, the nymph usually 
