30 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 68 



On page 509 Burmeister further says : 



The generally known means of defense of the bomb-beetle (Brachynus 

 crepitans) is of a peculiar description; it consists in its ejecting from its 

 anus against its enemy a vapoury moisture accompanied by a slight sound, 

 and which vapour has great resemblance to the gas of aquafortis. 



We have before noticed some peculiar organs of secretion in several 

 larvae, as for instance, in that of Pieris machaon, which are projected at the 

 approach of danger ; they appear, in fact, to be glandular organs which partly 



secrete odours and partly liquids, for the purpose of chasing the enemy 



Among the beetles similar organs are found in the genera of Cantharia and 

 Malachms, which in these are seated at the sides of the thoracic and ventral 

 segments, and are likewise projected in time of danger. 



Kirby and Spence (1823) remark that a fly, Hemerohius perla, 

 and an ant, Formica fcetida, emit an odor similar to that of human 

 ordure. Formica fuliginosa imparts a strong odor to everything it 

 touches. Many wild bees (Melitta and Andrena) are distinguished 

 by their pungent and alliaceous odor. Crabro Uavum, a wasp, emits 

 a penetrating odor like that from ether. 



Miiller (1878 c-d) claims that odors may have been acquired by 

 butterflies either for protection or to attract the opposite sex. In 

 most cases protective odors appear to be equally strong in both sexes. 

 Sexual odors may be divided into the following classes : ( i ) Those 

 which attract or allure the opposite sex from a distance, and (2) those 

 which excite the opposite sex during courtship. The male of Didonis 

 bihlis is able to emit as many as three distinct odors. When seized 

 either sex of this butterfly protrudes a pair of protuberances from 

 between the fourth and fifth abdominal terga ; these protuberances 

 emit a strong disagreeable odor. The male has a second pair of 

 similar protuberances between the fifth and sixth terga ; these emit 

 an agreeable odor. The wings of the male emit a musky odor. In 

 butterflies as a rule, Miiller says that the scent-producing organs 

 of males are located on the wings, but in a few genera (Danais, 

 Lycorea, I tuna, Morpho, and Didonis) they are found on the abdo- 

 men, and in some Hesperidse on the hind legs. Relative to moths 

 these organs lie on the abdomen or legs, although not wanting on the 

 wings. 



Rye (1878) reports that a particular water beetle found in India 

 emits a liquid, resembling walnut juice, which gives off a strong but 

 not an unpleasant odor. 



Lelievre (1880) found that both sexes of Thais polyxena emit 

 an odorous exhalation. 



