CLASSIFICATION I 
Ww 
tera) and Embuide being transferred doubtfully to Orthop- 
tera. 
Enderlein’s recent and thorough studies confirm the view 
that Termitide, Embiidze, Psocidze and Mallophaga constitute 
a single order. 
5. Plecoptera.— Metamorphosis direct. Antenne long, 
multiarticulate. Mouth parts mandibulate. Prothorax large. 
Wings two pairs, membranous, coarsely and complexly reticu- 
late; equal or else hind wings larger 
and with an ample plicate anal area. 
Abdomen with ten segments and usu- 
ally a pair of long multiarticulate cerci. 
Nymphs thysanuriform, aquatic ; adults 
unique in having tracheal gills. Ex- 
ample, Preronarcys. (Pigs 8 jaan 
single family, Perlide, comprising two 
hundred species. 
6. Ephemerida. — Metamorphosis 
direct. Antennz bristle-like. Mouth 
parts mandibulate, but atrophied in 
the adult. Prothorax small. Wings 
membranous, minutely reticulate; hind 
pair much the smaller, rarely absent. 
A chicken louse, Menopon. ; 
ene Abdomen slender, with ten segments 
and three or two very long multi- 
articulate cerci. Integument delicate. Nymphs thysanuri- 
form, aquatic. Example, Hevragema (Fig. 19). Three hun- 
dred species. 
7. Odonata.—Metamorphosis direct. Antenne inconspicu- 
ous, bristle-shaped. Mouth parts mandibulate. Prothorax 
small. Wings four, elongate, subequal, similar, membranous, 
minutely reticulate, with a costal joint, or nodus. Abdomen 
slender, with ten segments. Nymphs thysanuriform, aquatic. 
Example, Libellula (Fig. 20). About two thousand species 
have been described. 
8. Thysanoptera (Physopoda).— Metamorphosis direct, 
