v,:.i~ . 



ANAL GLANDS OF BEETLES 373 



high up and spurting the contents of the glands right and left." 

 The glands (Fig. 366, i) are two reddish brown, somewhat bilobed 

 sacs, and extend from the base of the last up to the middle of the 

 2d abdominal segment, with an average length of 6.5 mm. The 

 liquid stains the human skin, has an acid reaction, with a peculiar, 

 " intensely penetrant odor, causing the eye to lachrymate. It is 

 soluble in water, alcohol, and ether. Boiled with concentrated sul- 

 phuric acid and alcohol an ethereal aromatic vapor is produced, 

 indicating the presence of one or more organic acids, though neither 

 formic or acetic acid could be detected." Williston has observed the 

 same habits in seven other species of Eleodes, all ejecting a pungent 

 vile-smelling liquid, one species (E. longicollis) ejecting a stream of 

 fluid from the anal gland, backwards sometimes to the distance of 

 10 cm. or more, and he regards these beetles as '/ the veritable skunks 

 of their order." Leidy briefly describes the odoriferous glands of 

 Upis pennsylvanica. 



The anal glands consist, according to Meckel and also Dufour, of 

 'two long, simple, flexuous coeca with reservoirs having two short 

 excretory ducts situated near the anus (Siebold). 



Glands like those of Eleodes found in Blaps mortisaga are de- 

 scribed in detail by Gil son (Fig. 366, 2). They form two pouches or 

 cuticular invaginations situated in the end of the abdomen on the 

 sides of the end of the intestine and unite on the median line under- 

 neath the genital organs, forming a very short tube with a chitinous 

 wall, continuous with the cuticle of the last abdominal segment. 

 Into each pouch open a large number of fine slender lobules varying 

 in shape, giving a villous aspect to the surface. These lobules are 

 composed of as many as fifty unicellular glands, each of which is 

 composed of four parts : (1) A radiated vesicle, (2) a central sac, 

 giving rise (3) to a fine excretory tube, and (4) a sheath near the 

 origin of the excretory tube. These are all modifications of the 

 cytoplasm of the cell with its reticulum; the nucleus with its chromo- 

 somes is also present, but situated on one side of the central sac. 

 The fine excretory tubules form a bundle passing down into the 

 mouth of each lobule. 



Similar glands, though usually smaller, which have not been carefully exam- 

 ined, occur in Carabus (Fig. 366, 3) and Cychrus, which eject from the vent a 

 disagreeable fluid containing butyric acid (Pelouse). The bombardier beetle 

 Brachinus, with its anal glands, ejects a jet of bluish vapor accompanied with 

 a considerable explosion, which colors the human skin rust red ; it is caustic, 

 smells like nitrous acid, and turns blue paper red. Westwood states that indi- 

 viduals of a large South American Brachinus on being seized "immediately 

 began to play off their artillery, burning and staining the flesh to such a degree 



