338 ANNUAL OF SCIENTIFIC DISCOVERY. 



formic acid, as can be seen by the red tracks the ants will then make 

 in running over litmus paper. The musky secretions of these insects 

 of different orders could not proceed from the plants which serve to 

 support the adults or larva, whilst the odor of fennel exhaled by 

 Papilio machaon, as Martin informs me he has often determined, is 

 explained by the vesicles of essential oil of that odor which are scat- 

 tered over the mnbeUiferae, on which the caterpillar lives. Some in- 

 sects exhale agreeable odors ; thus the stapliylinus odens gives off the 

 odor of apples (pomme de reinette), or of nitrous ether; the coleop- 

 tera known by the name of Aromia mo*cliata does not exhale the 

 odor which its name indicates, but that of the essence of Levant roses. 

 It furnishes a sweet and persistent perfume, and the secretion is anal- 

 ogous to that of the willow, on which it feeds and lives. Both sexes 

 are odoriferous. 



The odor of the rose, sometimes not very pure and mixed with an- 

 other odorous substance, is found in the Cicindela campestris and 

 hybrada ; the odor is analogous to that of the products obtained by 

 treating essence of turpentine with nitric and sulphuric acids. The 

 males particularly present the secretion. Nothing is less known than 

 the nature of the essence of roses, a mixture of several substances, 

 which is obtained, not, as the treatises on chemistry and pharmacy 

 say, by distilling the flowers of the rose, but, according to Boisduval, 

 by the distillation of the root of a Convolvulus. It is well known, 

 and examples are furnished by this continually in organic chemistry, 

 that the same carbides of hydrogen can be met with in very different 

 species, whether animal or vegetable. Without attaching too great 

 importance to the connection between the two kingdoms of organic 

 nature, we may remark that the plant commonly known as musk 

 (mimulus moschatus), on account of the odor of its yellow flowers, 

 only presents this odorous secretion in its organs of reproduction. 



Laboulbene regards the secretions of odoriferous materials in insects 

 as being naturally of two groups. Sometimes they proceed from 

 Liquids which exude from all parts of the body, as in cochineals ; or 

 they are dependencies of the buccal apparatus, as in the sylphs and 

 different scarabaei that disgorge an infectious liquid here they be- 

 long to both sexes, and may exist in the larvse; sometimes, on the 

 other hand, and such are the musky secretions of the sphinx, the 

 odoriferous secretions only exist in the adults, are special to the 

 males, only appearing rudimentary in the females thus, in the cicin- 

 delidas, they are due to connected glands disposed in a species of ele- 

 gant arborization around the testicular apparatus, in a manner analo- 

 gous to the arrangement of the odoriferous glands of the musky 

 Hiammiferae, where the glands are largest in the male and are situated 

 near the genital organs. 



The production of musky matter seems to belong, in tropical coun- 

 tries, to the warm, humid, vegetable soils. Several travellers relate 

 that they were struck with the strong odor of musk exhaled from the 

 earth, especially in the morning, in the forests of the isles of Sunda, 

 and in Central America. Without speaking of Jacquinot, de Quoy, 

 and Gaimard, etc., Humboldt may be cited with reference to the 

 musky odor which is produced in the arid plain of Cumana, after 

 heavy inundations. He attributes it to the debris of jaguars, tiger- 



