6o SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 68 



shaped ampulla arises at the center of the vesicle and runs to the 

 outside of the vesicle where it continues as the secreting tubule, which 

 winds about considerably, passing through the lumen of the lobe in 

 order to open into the reservoir. The sheath of the tubule arises 

 inside the cell but encloses the tubule for only a short distance. The 

 secretion is an odorous oil in which swims a considerable number 

 of crystalline and yellow needles. 



Leydig (1890) says that the glands of Anchomenits deviate from 

 those of Brachinus in that they do not consist of long pouches, but 

 of round sacs similar to those in carabids. He is not certain how 

 the secreting tubules arise in the cells ; Leydig in 1859 was the 

 first to describe the finer structure of these unicellular glands. 



Porter (1895) experimented with eight individuals of Eriopis 

 convexa (Coccinellidae), one of Chelymorpha varians (Chryso- 

 melidae) and five of Lcemosthenes complanatus (Carabidse) . In all of 

 these he concludes that the liquid emitted by or near (por) the 

 anus is not the product of a secretion, but it is blood because this 

 liquid and some blood taken directly from the dorsal blood vessel 

 both contain corpuscles (leucocytes) of the same form, same dimen- 

 sions, same coloration, similar micro-chemical reactions and the same 

 amoeboid movements. 



Bordas (1898) describes the anal glands of Dytiscidae as a very 

 voluminous structure. They are paired and consist of two white, 

 intestinelike tubes, wound into an ovoid mass and located in the last 

 abdominal segments. The gland consists of the three following 

 layers: (i) The outer one is a thin peritoneal membrane; (2) the 

 middle one consists of muscular fibers ; and (3) the inner one lining 

 the lumen of the collecting tube is an epithelial layer composed of 

 rectangular secreting cells. The collecting tube runs into a reservoir 

 whose muscular layer is more powerful than that in the gland just 

 mentioned. When excited, the insect discharges a yellowish liquid 

 into the surrounding water, making a slight brownish cloud by the 

 aid of which the insect may easily escape its enemy. The same author 

 (i899a-b) says that when Brachinus is disturbed an acrid liquid, is 

 discharged which produces a crepitation ; the liquid at once changes 

 into a little cloud of pungent and corrosive vapors and the detona- 

 tions may be repeated 10, 15, or 20 times in succession. He has 

 studied these glands in several genera of Carabidse and in each species 

 he found grapelike unicellular glands, secreting tubules, a collecting 

 tube, a reservoir, and an efferent canal leading into the cloaca. Bordas 

 (1899c) asserts that 24 genera and 56 species of Coleoptera, repre- 



