Fig. 99.—Poison-apparatus of the Bee.
gl.ac, Acid gland and its two branches; V, poison-sac; gl.al, alkaline gland; gor, gorget.
(After Carlet: figure borrowed from Hommel.)
The poison-organs, which have been well studied, especially by Leuckart,[125] Leydig,[126] Carlet,[127] and more especially by L. Bordas,[128] Janet,[129] and Seurat,[130] always include two and sometimes three kinds of glands: the acid gland, the alkaline gland or gland of Dufour, and the accessory poison-gland ([fig. 99]).
The acid gland comprises a glandular portion (which sometimes takes the shape of a long flexuous tube, always bifid at its extremity, sometimes that of two tubes, simple or ramified, or again is composed of a bundle of cylindrical, simple or multifid canals), a poison-sac or reservoir, ovoid or spherical in shape, and an excretory duct, which is usually short.
The alkaline gland, or gland of Dufour, exists in all Hymenoptera, and presents the appearance of an irregular tube, with a striated surface and a spherical or conical upper extremity. Its excretory duct opens, beside that of the acid gland, at the enlarged base of the gorget of the sting ([fig. 100]).
Fig. 100.—Interior of the Gorget of the Bee, seen from its Posterior Aspect.
cv, Poison chamber; gor, gorget; st, stylet; ca, piston. Between the two stylets is seen the cleft fa, by which the air is able to enter into the air-chamber cai.
(After Carlet: figure borrowed from Hommel.)
The accessory poison-gland, which is lanceolate or ovoid in shape, consists of a small, granular mass, the extremely narrow excretory duct of which opens at almost the same point as that of the alkaline gland. It does not exist in all Hymenoptera.