NATURAL HISTORY STUDIES 



But there are many caterpillars that are not silk- 

 spinners. 



Returning to the structure of the caterpillar, we 

 see that each of the first three rings behind the 

 head bears a pair of five -jointed legs ending in a 

 claw. Behind this region there are ten rings, but 

 in most cases the ninth is telescoped and difficult 

 to see. Short unjointed legs, ending in peculiar 

 gripping structures, occur on the third, fourth, 

 fifth, and sixth of these rings, and a large pair 

 (sometimes changed into protrusible whips) is borne 

 on the tenth and last. There are, of course, many 

 departures from the rule that there are five pairs 

 of these unjointed legs or "pro-legs." Thus in 

 the " loopers," which move in a characteristic way, 

 familiar in the common magpie moth, there are 

 only two pairs. 



There are paired breathing apertures, leading 

 into air tubes, on many of the rings, and the body is 

 often thickly covered with hairs, bristles, spines, 

 or warts. Inside the body there are, of course, 

 organs corresponding to those that we possess 

 brain and nerve cord, food-canal, muscles, air- 

 tubes, heart, and so on. 



Activities of Caterpillars 



Most caterpillars lead an active life, moving about 

 in search of food. Some rove by day and others 

 by night. In some dim way they are aware of the 

 suitable food-plants, passing others by, and certain 

 kinds may often be seen exploring in a business- 

 like fashion. The procession caterpillars, which 



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