SCALE-INSECTS. 



"The family includes a number of quite different-looking 

 insects, as the True Scale-insects or Bark-lice, the Mealy- 

 bugs, and others for which we not even have a popular 

 name. They are a very anomalous family, and the 

 species differ very greatly in appearance, habits, and 

 metamorphoses from the other allied families already 

 described. Even the sexes of the same species differ as 

 much in the adult stage as do the members of different 

 orders. The males, unlike all other Hemiptera, undergo a 

 complete metamorphosis, but possess only a single pair of 

 wings. The hind wings are simply represented by a pair 

 of club-like halteres, as is the case in the Diptera or Two- 

 winged Flies. Each of these halteres is furnished with a 

 hooked bristle, which fits in a pocket on the upper wing 

 on the same side. The males possess no mouth. . . . 

 The female is always without wings and has either a scale - 

 like or a gall-like form, and is covered with larger or 

 smaller scales of wax, which may be in the form of powder, 

 of large tufts or plates, of a continuous layer, or of a thin 

 scale. Beneath this protecting substance lives the insect. 

 . . . All scale-insects are plant-feeders, and like the 

 plant-lice obtain liquid food by means of suction. But 

 not all are injurious, as some furnish dye-stuffs, shellac, or 

 wax" (Lugger). 



All scale-insects are injurious to the plants upon which 

 they feed, but what Prof. Lugger meant was that, as far 

 as man is concerned, the harm which certain species do is 

 more than counterbalanced by the benefits we derive 

 from them. The manna which fed the Children of Israel 

 was honey-dew secreted by a scale-insect. It is still 

 eaten. Shellac is derived from the scale of Carteria lacca 

 in India and the insect itself contains a red substance 

 called "lake." Before the present extensive use of aniline 

 dyes, coloring matter was derived from a number of 

 different species of Coccidae, especially from the Cochineal 

 Insect, Coccus cacti, of Mexico. The natives of the island 

 of St. Vincent make necklaces from the encysted pupae of 

 Mar gar odes, calling them "ground-pearls." 



