MEANS OF DEFENCE OF INSECTS. 251 
tata, L.) when taken ejects from its joints a yellow fluid 
which yields a powerful but not agreeable scent of opium. 
—Asilus crabroniformis, L., a dipterous insect, once 
when I took it, emitted a white milky fluid from its pro- 
boscis, the joints of the legs and abdomen, and the anus. 
—The common scorpion-fly, likewise, upon the same 
occasion ejects from its proboscis a brown and fetid 
drop*. Some insects have peculiar organs from which 
their fluids issue, or are ejaculated. Thus, the larvee of 
saw-flies when taken into the hand cover themselves with 
drops, exuding from all parts of their body, of an un- 
pleasant penetrating scent >. That of Tenthredo lutea, L. 
of the same tribe, from a small hole just above each spi- 
racle, syringes a similar fluid in horizontal jets of the 
diameter of a thread, sometimes to the distance of more 
than a foot°.—The caterpillar of the great emperor moth 
(Bombyx Pavonia major, ¥., Saturnia Pyri, Schrank) 
also spirts out, when the spines that cover them are 
touched, clear lymph from its pierced tubercles 4.— Wil- 
lughby has remarked a curious circumstance with re- 
spect to a water-beetle (Dytzscus cinereus, Marsh.) which 
ought not to be overlooked. A transverse line of a pale 
colour is observable upon the elytra of the male; where 
this line terminates certain oblong pores are visible, from 
which he affirms he has often seen a milky fluid exu- 
ding*; and what may confirm his statement, I have more 
than once observed such a fluid issue from Dytisci of the 
same family.—The caterpillar of the puss-moth (Bombyx 
vinula), as well as those of several other species, has a 
2 De Geer, 11.734. » Reaumur, v. 96. ¢ De Geer, ii. 987 — 
4 Rosel,iv. 162. De Geer, i, 273. 
© Rai. Hist. Ins. 94. n. 3. 
