INSECTS INJURIOUS TO DRUGS 489 



commonly enough represented and known in the case of the familiar 

 flour or cheese mite, are minute, rounded-oval, eight-legged insects, with 

 the mouth parts arranged to form a piercing beak. The body is not 

 divided into head, thorax, and abdomen, as is the case with other insects, 

 but all these parts are coalesced or merged into a single mass. While 

 many mites suck the blood from animals or the juices from plants, many 

 others feed on "dry food." Among these are the flour and cheese mites, 

 and sugar mites with soft, smooth, whitish body (see Fig. 263), and belong' 

 ing to the genera Tyroglyphus, Rhizoglyphus, and Glyciphagus. Many 

 species of these genera of mites, besides being found in sugars, meals, 

 and other vegetable products in the store-room, attack dried animal re- 

 mains, cantharides suffering severely from the ravages of several species of 

 Glyciphagus (see Fig. 264). The presence of the mites in the cantharides 



FIG. 263. Sugar Mite. FIG. 264. A Cantharid-eating Mite (Glyci- 



phagus spinipes). (Fum. and Rob.) 



jars is indicated by much powder and broken bits of the beetles gathering 

 on the bottom of the jars. In this mass of powder and fragments can be 

 seen with the naked eye many small, moving, whitish specks, the mites. 

 These specks, examined under the microscope, will reveal the character- 

 istic shape and appearance of the mites. 



The most abundant pest in the pharmacal store-rooms appears to be a 

 small brown beetle, Sitodrepa panicea, belonging to the family Ptinidae, 

 a family whose members, in both larval and adult stages, feed on dead, 

 dry vegetable and animal matter. This family comprises a number of 

 small beetles, rarely exceeding a quarter of an inch in length, and usually 

 brownish in color. A conspicuous and distinctive character is the hood- 

 like prothorax, the head being so bent or drawn back under it as to be 

 almost concealed (see b, Fig. 265). Sitodrepa panicea, the especially 

 abundant species of this family, is from 2 to 3 mm. long, with a 

 brown, subcylindrical body. It is almost entirely covered with many fine, 

 short, yellowish hairs, which, on the upper surface of the body, are ar- 

 ranged in parallel longitudinal lines; the upper surface of the body (strictly, 



