PSYCHE. 391 
glands which furnish the poisonous se- 
cretion for the sting of bees and wasps. 
I have not discussed these glands further 
in this paper, because they are rather 
internal than external glands; for: like 
reasons I have not referred to the silk- 
glands of lepidopterous and hymenopte- 
rous larvae. The literature of impor- 
tance upon the subject of the silk-glands 
of lepidoptera can be found in a disser- 
tation by Helm,” in 1876; and papers 
by Dewitz, ?*, in 1875 and 1877, and 
by Forel,” in 1878, give a clue by which 
to trace the literature upon the stinging 
organs of hymenoptera. 
The glands of the larva of <Aftacus 
cecropia and sealed 
until broken open by some external 
agency, may be termed passive glands, 
while those glands which pour out their 
secretion in direct response to some vol- 
untary or reflex action of the insects, as 
do the foot-glands. of Musca, the sting 
of the bees and many other glands, 
may be termed active glands. But there 
are glands characterized by still greater 
activity than those already mentioned. 
Tf the larvae of certain species of Cim- 
bex are suddenly disturbed, they will jet 
out, as observed by Bonnet® (v. 1, p. 
470, 473, 485), a clear yellow fluid, of 
disagreeable odor, from openings along 
their sides. In the case of a German 
species of Cimbex I have seen this fluid 
thrown by the larva to a distance of 
several centimetres, altho Frisch,** who 
first mentions this secretion, in 1736, 
apparently only saw it flow from the 
openings. 
Upon disturbance, the larva of the 
. 
Hyperchivia to, 
European bombycid, Harpyia vinula, 
raises its head and jerks it from side to 
side, throwing a strongly acid fluid from 
a gland, the opening of which is on the 
ventral side of the first thoracie segment. 
The propulsion is here partly produced 
by the rapid jerking of the head, and 
partly by pressure upon the receptaculum 
or lumen of the gland within the body. 
This gland, or at least its secretion, was 
noticed by de Geer” in 1750, and more 
fully in 1755 by Bonnet,” who described 
the secretion as a true acid, sharp, sour, 
and biting. Later, besides many brief 
notes on this gland, may be mentioned 
more extended descriptions by Miiller,” 
Amoreux,”® Jérdens, and Rengger.” 
I have not observed whether the larvae 
of the common American species of 
Harpyia (Cerura) possess this power of 
throwing a defensive fluid or not, and 
Lintner,*! as well as French,” in descrip- 
tions of the American larvae, make no 
mention of such power. The soft skin 
of the larva of Harpyia vinula evagin- 
ates itself about the orifiice, on the first 
thoracic segment, where the gland dis- 
charges its fluid, forming four points’ 
which are well figured by Miiller and 
Jérdens, in the books cited above. 
Within, the duct of the gland passes to 
the right of the displaced central nervous 
system, as described and figured by Mrs. 
Dimmock, in Psycun, v. 3, p. 540-341. 
I pass by, with mention only, the 
openings which pour out an odorous 
yellow fluid from the joints of the legs of 
species of coccinellidae, chrysomelidae and 
meloidae, for further notice of which I 
refer to papers by Leydig’® (p. 37-38) 
