1916] Rejlex " Bleeding" of Epilachna 213 



The taste, volatility and odor of the secretion seem to be 

 due to a peculiar principle called cantharidine, which is a vol- 

 atile, acrid, bitter soHd, crystalHzing into four-sided prisms. 

 It is thus seen why the liquid evaporates so quickly when 

 ejected, leaving yellow flakes on the integument. 



A few investigators have performed many experiments with 

 various warm and cold-blooded animals by feeding them some 

 of the secretion. De Bono (1889) used many insects, frogs, 

 toads, guinea pigs and coyotes. He found that the secretion 

 from Timarcha pimeliodes has a manifest action on the heart of 

 warm and cold-blooded animals, and that it has an injurious 

 effect on Musca communis, Sarcophago carnaria, although little 

 or no injurious effect on other insects. Lutz (1895) remarks 

 that the secretion from the same insect may kill flies within a 

 few minutes and is poisonous for warm and cold-blooded 

 animals. Porta (1903) fed the secretion from Coccinella 

 7-punctata to various animals. He says that the liquid exercises 

 a poisonous influence upon the organism of both warm and 

 cold-blooded animals, and his experiments show that it is 

 injurious to the brain. He found, however, that it does not 

 exercise any influence upon insects. For Coccinella he thinks 

 that the secretion probably serves as a means of defense by the 

 odor which is offensive to other insects and perhaps this yellowish 

 Hquid indicates to them a harmful substance. 



The odor of the secreted Hquid, besides serving as a means 

 of defense, probably also serves as a means for individual and 

 sexual recognition. The secretion of a given species perhaps 

 emits a specific odor by means of which the different individ- 

 uals and sexes of that species recognize one another. 



DISCUSSION. 



Lacordaire (1838) was one of the first investigators to 

 describe the phenomenon of ejecting liquid from various parts 

 of the body of certain insects. He says that when Dytiscus and 

 Gyrinus are picked up, they emit through the articulations 

 between the head, thorax and abdomen a milky and fetid fluid. 

 Meloe emits from the articulations of the legs a yellowish-orange 

 liquid whose odor is not disagreeable. CoccinelHdse and 

 ChrysomeHdaj emit anjanalogous liquid at the same places, but 

 it has a different odor and is quite strong. 



