ARTHROPODA 113 



grubs. The Diptera number about forty thousand. 

 Among them are the mosquitoes (Culex)\ Hessian fly 

 (Cecidomyid), so destructive to wheat; daddy longlegs 

 or crane fly (Tipula), resembling a gigantic mosquito; 

 the wingless flea (Pulex) ; besides the immense families 

 represented by the house fly (Mused) and bot fly (CEstrus). 

 5. Lepidoptera, or " butterflies " and "moths," are 

 known chiefly by their four large wings, which are 

 thickly covered on both sides by minute, overlapping 

 scales. The scales are of different colors, and are often 

 arranged in patterns of exquisite beauty. They are in 

 reality modified hairs, and every family has its particular 



FIG. 70. Scales from the Wings of various FIG. 71. Part of the Wing of a Moth 



Lepidoptera. (Santia), magnified to show the 



arrangement of scales. 



form of scale. The head is small, and the body cylin- 

 drical. The legs are of but little use for locomotion. 

 All the mouth parts are nearly obsolete except the maxil- 

 lae, which are fashioned into a " proboscis " for pumping 

 up the nectar of flowers. The larvae, called "cater- 

 pillars," have a wormlike form, and from one to five 

 pairs of abdominal legs, or " false legs,",, in addition to 

 the three on the thorax. The mouth is formed for mas- 

 tication, and (except in the larvae of butterflies) the lip 

 has a spinneret connected with silk glands (Fig. 75). 



There are two groups : the gay butterflies, having 

 knobbed or hooked antennae, and flying in the day only, 

 forming one group ; and the moths, which generally 

 DODGE'S GEN. ZOOL. 8 



