236 THE SCIENCE OF LIFE. 



Order 5. Diptera, or two- winged Flies; have the hinder 

 pair of wings replaced by " poisers/' or "halteres" A 

 few species are wingless. The eyes are large, with many 

 facets ; the tongue terminates in a fleshy knob, and the 

 rest of the mouth is suctorial, and furnished with fine 

 lancets ; the thorax is globular, and the legs slender. 

 The larvae are footless grubs. Among them are House- 

 flies, (Musccz?) (Fig. 138,) Gnats, (Culicidce^) Crane-flies, 

 ( Tipulida, ) Forest-flies, ( Hippoboscce, ) and Gad-flies, 

 (Gabrinufo!) The wingless Flea (Pulex) is also placed 

 in this order. 



Order 6. Lepidoptera, (lepis, scale ; ptcron, wing,) in- 

 cludes Butterflies and Moths. They have four large 

 wings, thickly covered on both sides with minute over- 

 lapping scales, of different colors, and often arranged in 

 patterns of exquisite beauty. These scales are epider- 

 mic appendages of a similar nature to hairs, and every 

 family has a special form of scale. The head is small, 

 the body is cylindrical, and the legs are little fitted for 

 locomotion. The mouth is a proboscis, or coiled tube, 

 sometimes an inch long. The caterpillar, or larva, has a 

 worm-like form, and from one to five pairs of abdominal 

 legs, in addition to the six on the thorax. The mouth 

 is formed for mastication. 



There are three groups : the gay Butterflies, (Fig. 

 138,) having knobbed or hooked antennae, flying in the 

 sunshine only, and keeping their wings vertical when at 

 rest ; the dull-colored Sphynges, or evening Moths, with 

 antennae thickened at the middle, and flying at twilight ; 

 and the nocturnal Moths, whose antennae are thread- 

 like and often feathery, and which prefer the night. 



