444 THE INSECTA. § 347. 
Coleoptera, these anal glands secrete a caustic fluid which has a penetrating 
and more or less aromatic odor. They are somewhat ramified, or composed 
of vesicles disposed botryoidally, and open into one or several long, excre- 
tory ducts.©’ These last open into two pyriform, muscular reservoirs, whose 
powerful contractions expel, as a means of defence, the secreted fluid. The 
Formicidae, also, have, in the anal region, a glandular apparatus from 
which they eject a caustic, acid fluid. This apparatus is single and com- 
posed of one reservoir whose neck opens into a simple tube.” The larvae 
of Harpyia, also, defend themselves by ejecting an irritating liquid secreted 
by a glandular sac, which opens directly back of the head on the under 
surface of the first segment of the body. 
Among the Hymenoptera, the females of the Vespidae, Fossores, An- 
drenidae, and Apidae, have, in the anal region, a glandular apparatus which 
secretes a poisonous fluid introduced by means of a holléw sting into the 
tissues of their prey or enemies.© This Poison-apparatus is composed of 
two long tubes which are sometimes very ramose.® The intimate struc- 
ture of these tubes resembles that of the salivary glands.“ The two 
poison-glands are sometimes isolated, sometimes united into a common 
canal, and their product is poured into a pyriform reservoir, which has 
thin but contractile walls, whose longer or shorter excretory duct opens. 
into the sting.“ This sting is formed by the intimate union of two lateral 
pieces, and plays in a cleft horny sheath. Often, its extremity is covered 
with backwardly-pointing denticles.“” Both the sheath and the sting have, 
at their base, a peculiar muscular apparatus by, which they are protruded 
and withdrawn. 
near the arms, ejaculate a highly stinking liquid. 
With the Silphidae, where this apparatus is single, 
the reservoir opens laterally into the rectum ; see H. 
Meckel, in Muller’s Arch. 1846, p. 47, and L. Du- 
four, Ann. d, Sc, Nat. VIII. 1826, p. 15, III. Pl. X. 
fig. 3, 4, 5, Pl, XIII. fig. 5, 7 (Dytiscus, Gyrinus 
and Sitplta). With Gryliotalpa, the anal glands 
consist of small lobular bodies inserted on the re- 
servoir which receives their product: see ZL. Du- 
‘our, Becher ch. sur les Orthopt, &e. +) p. 346, Pl. 
I. fig. 1 
5 With, ‘the Carabidae, and Staphylinidae ; see 
L. Dufour, Aun. d. Sc. Nat. VIII. 1826, p. 6; 
IL. Pl. XX. XXL; IMI. Pl. X.; and VII. Pl. XIX. 
XX.; J. Miller, De Glandul. Struct. &c. Tab. I. 
fig. 13-18 ; and Stein, Vergl. Anat. u. Physiol. d. 
Insekt. 1847, Taf. I. fig. 4, g. g. (Dianous) and 
Taf. IIL. fig. 3, 1. n. (Oxytelus). 
6 With Brachinus, as is well known, this prod- 
uct is so volatile as to immediately become gase- 
ous on its ejection.* 
7 See L. Dufour, Recherch. sur les Orthopt. &c. 
p. 413, Pl. VIL. fig. 86. 
8 The Bees, which have a poison-apparatus of 
this kind, ought to be regarded as females whose 
genital organs are undeveloped. Many fossorial 
Hymenoptera, which feed their young with insects, 
* [ § 347, note 6.] For the peculiar glandular 
apparatus for this purpose, with Brachinus, see 
Karsten, in Miller’s Arch. 1848, p. 367. Con- 
trary to other Zootomists, this observer regards 
this apparatus as of a urinary nature, for he states 
that an analysis of its secretion furnishes a product 
analogous to urea. — Ep. 
wound these last with their sting, that they may be 
mastered, and conveyed the more easily to the 
nest. Indeed, some carry their prey into their 
nests transfixed with the sting. (See my Observ. 
quaed. de Oxybelo atque Miltogramma, 1841, p. 
11.) The wound does not always kill the insect, 
but simply disables it, so that they remain fresh 
for several days by the side of the larvae for whose 
food they are to serve. 
9 There are two simple tubes with Vespa, Scolia, 
Crabro, Halictus, Apis, &c.; but they are ram- 
ified with Pompilus, Philanthus, Larra, Bom- 
bus, &c. 
10 For the intimate structure of these poison- 
glands, see H. Meckel, in Miller’s Arch. 1846, p. 
45, Taf. III. 
11 This poison-apparatus is described more in 
detail in the works of Swammerdamm, Bib. der 
Nat. p. 183, Taf. VIII. (Apis); Brandt and 
Ratzeburg, Mediz. Zool. IT. p. 203, Taf. XXV. fig. 
39-42; Ramdohr, Abhandl. tib. d. Verdauungs- 
werkz. &c, Taf. XIV. fig. 5 (Pompilus), and 
Suckow, in Heusinger’s Zeitsch. II. Taf. XIV. 
fig. 38, 46 (Apis and Crabro).t 
12 See Swammerdamm, loc. cit. Taf. XVIII. fig. 
3. 
t [ § 347, note 11.] The poison of the poison 
apparatus in the Hymenoptera has been investi- 
gated by Will (Schleiden and Froriep’s Not. 
1848, Sept. p. 17) who found, with Ants, Bees, and 
‘Wasps, that this product consisted of formic acid 
and a whitish, fatty, sharp residuum, the former 
being the poisonous substance. — Ep. 
