INSECTS AND THEIR CLASSIFICATION. 45 



through a microscope this may appear a trifle ferocious. 

 They are winged, probably suck their food, and have 

 incomplete metamorphosis. The Mecoptera is the order 

 of the scorpion flies, so called because some of the order 

 have the anal end of the abdomen shaped like the sting 

 of a scorpion. The mouth parts are beak-like, but with 

 mandibles at the end of the beak. The insects have four 

 wings and reproduce by complete metamorphosis. 



The Trichoptera have hairy wings, four of them, and 

 they use them only in the adult stage. They are called 

 caddice or caddis flies. The larvs, or caddis worms, are 

 highly prized as bait by old fishermen in England. 

 These queer larvas make a case of sticks, sand, or straw 

 about themselves, then stick out the head and the thorax, 

 and go crawling about in the water for food. The adults 

 look considerably like small moths. 



