24 BCLLETIX OF WISCONSIN NATURAL HISTOKY SOCIETY. VOL. 4, NOS. 1-2. 



ISONITRILES. 



Both sexes of the large Tarantula-hawk {Pepsis spp.) produce 

 a distinct isonitnle odor when first captured. This is ouite 

 noticeable, although often modified by the scent of the honev that 

 they have eaten. 



The nasutes of an African species of Ptyotermes eject a 

 pungent stream from the head, the nature of which is thus treated 

 by Look ( 90) : "The fluid is clear and watery and does not stain 

 the hands. A smarting sensation in the eyes and nose is also 

 distinctly appreciable. The odor is even more disagreeablv 

 pungent and penetrating than that of Spirotreptus [a mvriapod 

 mentioned below] and has an almost nauseating quality which 

 pervades the nests and galleries of the species and can readily be 

 detected in houses attacked bv this termite [isonitriles] Like the 

 secretion of Polyzonium [another mvriapod referred to belowl the 

 liquid becomes sticky on exposure to the air, and the insect 

 enemies upon which it is squirted have their antennae stuck to 

 their bodies and are other^vise disabled." 



vegetable; extracts, etc. 



Large numbers of phytophagous insects acquire odors or taster 

 derived from their food plants, but these hardlv come in line with 

 the present discussion. 



Many of the Darkling beetles, and especiallv those belonging 

 to the genus Elcodcs secrete from anal glands' a fluid of an in- 

 tensely disagreeable odor, which some of the species can forciblv 

 eject for a distance of ten centimeters or more. The liquid stains 

 the skin brown, besides having a very penetrating odor and thus 

 resembles the secretion of Spirobohis (see special part) \ccorfl- 

 mg to Wilhston ('84) it is soluble in water, alcohol and ether has 

 an acid reaction, and can be esterified to an agreeably smellin- 

 ether by means of alcohol and sulphuric acid. He suggests from 

 this the presence of organic acids other than formic' or acetic 

 which latter he could not detect. Our commonest species, when 

 extracted with ether furnishes an extremelv malodorous com- 

 pound, suggesting extract of Taraxicum or opium. 



The exuded blood of many Coccinellidse has an opium-like 

 odor (Packard 98). The species of the ant genus Crrma.-/o -a.- - 

 tcr. squirt from their anus a white liquid which recalls the iuice 

 characteristic of the shelf-fungi. This odor is much more intense 

 in another ant. Pachycondla {v. special portion). 



