96 



CERTAIN PARASITIC INSECTS. 



109. Podura. 



the parasitic species, and other degraded, wingless forms that 

 do not always live parasitically, especially of their embryology 

 and cTianges after leaving the egg, than by years of study of 

 the more highly developed insects alone. Among Hymeuoptera 

 the study of the minute Ichneumons, such as the Proctotrupids 

 and Chalcids, especially the egg-parasites ; 

 among moths the study of the wingless can- 

 ker-worm moth and Orgyia; among Diptera 

 the flea, bee louse, sheep tick, bat tick, and 

 other wingless flies ; among Coleoptera, the 

 Meloe, and singular Sty lops and Xenos ; 

 among Neuroptera, the snow insect, Boreus, 

 the PoJura (Fig. 109) and Lepisma, and espe- 

 cially the hemipterous lice, will throw a flood 

 of light on these prime subjects in philosoph- 

 ical entomology. 



Without farther apology, then, and very 

 dependent on the labors of others for our 

 information, we will say a few words on some 

 interesting points in the natural history of 

 lice. In the first place, how does the louse 

 bite? It is the general opinion among physicians, supported by 

 able entomologists, that the louse has jaws, and bites. But 

 while the bird lice (Mallophaga) do have^ biting jaws, whence 

 the Germans call them skin-eaters {pdzfresser'), the mouth parts 

 of the genus Pediculus, or true louse, resemble in their structure 

 those of the bed-bug (Fig. 110), and other Hemiptera. In its 

 form the louse closely resembles the bed-bug, and the two groups 

 of lice, the Pediculi and Mallophaga, should be 

 considered as families of Hemiptera, though 

 degraded and at the base of the hemipterous 

 series. The resemblance is carried out in the 

 form of the egg, the mode of growth of the 

 embr5'0, and the metamorphosis of the insect 

 after leaving its egg. 



Schiodte, a Danish- entomologist^ has, it 

 seems to us, forever settled the question as to 

 whether the louse bites the flesh or sucks blood, and decides 

 a i:-oint interesting to physicians, i. e., that the loathsome disease 

 called phthiriasis is a nonentity. From this sofrce not only 

 many living in poverty and squalor are said to have died, but 



110. Betl-bug. 



