ENTOMOLOGY

SANITARY ENTOMOLOGYgrowing against these insects from the sanitary standpoint. Some ofthese insects contain substances in their bodies which are highly toxi(" asfor instance Sitophilua granarius, the granary weevil, contains thepoisonous substance cantharidin. There are numerous instances of thesickening of animals from eating weevily grain. Still more important isthe fact that where grain is accessible both to rodents and insects, certainparasitic worms pass out in the feces of the rodent in the egg stage,are eaten by the insect larvae in the grain, pass part of their life cyclein the insect, and the insect is then pos:;ibly eaten by a rodent, in whichthe worm completes its life cycle; or sometimes in our breakfast foodswe eat these parasitized insects and become infected with the worms. Forexample, the rat tapeworm, Hymenolepis diminuta (Rudolphi) infestsvarious species of rats, but sometimes is found in man. Joyeux hasproved that its commonest intermediate host is the meal moth, A.sopiafarinalis,which becomes infected by eating the tapeworm eggs, in thelarval stage. Grassi and Rovelli found the cysticercoid in the larva andadult of this moth and also in the earwig, A.nisolabis annulipes and thebeetles Akis spinosa and Scaurus striatu8. Joyeux found that the adultsof the granary beetle, Tenebrio molitor, easily took up the eggs. Acysticercoid or larval stage resembling the mouse tapeworm Hymenolepismicro8toma (Dujardin) has been found by Grassi and Rovelli in thebeetle Tenebrio molitor.The whole problem, therefore, of the control of stored food productinsects is of vital importance to the manufacturers of food.Syrup factories, sugar mills and refineries, ice cream factories, creameries,and candy factories offer great attractions to flies which mayalight on the exposed products and deposit with their feet, or in theirvomit or excreta, germs of disease taken up elsewhere, perhaps daysbefore when the fly was a larva breeding in excrement, and these germsmay find the sweets excellent culture media for extensive growth. Extraordinarymeans must be devised to keep flies away from such products.Packinghouses offer abundant attractions to many kinds of insects,many of which are serious disease carriers.Railroad trains are the means of conveying. from place to placedisease-carrying mosquitoes, flies, roaches, fleas, lice, bedbugs, and mites.Fumigation of railway cars is an essential entomological control measure.Dairies are often found to be the foci of the spread of typhoid fever,and knowing the propensity of the house fly we can see how readily itcan carry the organisms from the stools of a siek person to the milkpails in the dairy. There needs to be rigid control of flies in all dairies.These are but examples of many industries which have problems insanitary entomology.