300 
COMPARATIVE ZOOLOGY. 
('Cerambycidce ); and the destructive Weevils (Curculio* 
nidce ), with pointed snouts. 
5. Dipiera , or “ Flies,” are characterized by the rudi¬ 
mentary state of the hinder pair of wings. Although 
having, therefore, but one available pair, they are gifted 
with the power of very rapid flight. While a Bee moves 
its wings one hundred and ninety times a second, and a 
Butterfly nine times, the House-fly makes three hundred and 
thirty strokes. A few species are wingless. The eyes are 
large, with numerous facets. In some forms, as the House¬ 
fly, all the mouth-parts, except the labium, are rudimen¬ 
tary ; and the labium has an expanded tip, by means of 
Fig. 270.—Metamorphosis of the Flesh-fly (Sarcophaga carnaria ); a, eggs; 6, you»<* 
maggots just hatched; c, d, full-grown maggots; e, pupa; /, imago. 
which the fly licks up its food. In other forms, as the 
Mosquito, the other mouth-parts are present as bristles or 
lancets, fitted for piercing; the thorax is globular, and the 
legs slender. The larvae are footless grubs. The Diptera 
number about twenty-four thousand. Among them are 
the Mosquitoes ( Culex ); Hessian-fly ( Cecidomyia ), so de¬ 
structive to wheat; Daddy-long-legs {Tipula), resembling 
a gigantic Mosquito; the wingless Flea (Pulex) ; besides 
the immense families represented by the House-fly {Mus¬ 
ed) and Bot-fly {CEstrus). 
6. Lepidoptera, or “ But¬ 
terflies” and “Moths,” are 
known chiefly by their four 
large wings, which are thick¬ 
ly covered on both sides by 
cFiq. 271 . —Scales from the Wings of vari- 0Verla PP in g Scales. 
ous Lepidoptera. The scales are of different 
