84 ANIMAL BIOLOGY 



found near the head (Fig. 141). It has also from three 

 to five pairs of fleshy unjointed proplegs, one pair of 

 which is always on the last segment. How many pairs 

 of proplegs has the silkworm caterpillar? (Fig. 143.) 

 The measuring worm, or looper ? (Fig. 136.) The pupa 

 has a thin shell. Can you see external signs of the 

 antennae, wings, and legs in this stage ? (Fig. 143.) The 

 pupa is concealed by protective coloration, and is some- 

 times inclosed in a silken cocoon which was spun by the 

 caterpillar before the last molt. Hairy caterpillars usually 

 produce butterflies, and the naked ones usually produce 

 moths. Hairy ones are uncomfortable for birds to eat. 

 The naked and brightly marked ones (warning coloration) 

 often contain an acrid and distasteful fluid. The injuries 

 from lepidoptera are done in the caterpillar stage. The 

 codling moth (Fig. 141) destroys apples to the value of 

 $6,000,000 annually. The clothes moth (Fig. 171) is a 

 household pest. The tent caterpillar denudes trees of their 

 leaves. The only useful caterpillar is the silkworm (Fig. 

 143). In Italy and Japan many of the country dwellings 

 have silk rooms where thousands of these caterpillars are 

 fed and tended by women and children. Why is the cab- 

 bage butterfly so called ? Why can it not eat cabbage ? 

 Why does sealing clothes in a paper bag prevent the 

 ravages of the clothes moth ? 



Flight of Lepidoptera. — Which appears to use more ex- 

 ertion to keep afloat, a bird or a butterfly ? Explain why. 

 Of all flying insects which would more probably be found 

 highest up mountains ? How does the butterfly suddenly 

 change direction of flight ? Does it usually fly in a straight 

 or zigzag course ? Advantage of this ? Why is zigzag 

 flight unnecessary to moths ? Bright colors are protective, 

 as lepidoptera are in greatest danger when at rest on 



