282 



VENOMS 



Janet,^ and Seurat,^ always include two and sometimes three kinds 

 of glands : the acid gland, the alhaline 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 fiexuous 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). 



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. 



The stings of hive bees {Apis mellifica), 

 wasps {Vespa vulgaris), violet carpenter bees 

 (Xylocopa violacea), and humble bees (Bom- 

 hus lapidarius) cause considerable discom- 

 fort. The venom of the carpenter bee, which is of some strength, 

 has been studied by P. Bert, and I have myself made experiments 

 with that of the hive bee {A. mellifica). The venom extracted 



Fig. 100.— Interior of 

 THE Gorget op 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 bor- 

 rowed from Hommol.) 



' Comptes rcnilus cle VAcademie cles Sciences, 1898. 

 ^ Annales sc. Anat. Zoologie, 8^ serie, t. x., 1898. 



