132 



SOME SOUTH INDIAN INSECTS, ETC. [CHAP. XIII. 



especially characteristic of the Geometrida (literally "earth-measu- 

 rers "). commonly called " Loopers" or " Spanworms : " but in many 

 Noctuid larvae (e.g., Plusiand, Catocalince) some of the anterior 

 prolegs may be absent or little developed so that the caterpillar 

 progresses partly by walking in the ordinary waj and partly by 

 arching the segments on which the legs are ineffective, sue! 

 pillars being called " Semi-loopers." In some cases the prolegs, 

 though present, may be greatly modified; in the case of the lobster 

 caterpillar {Stauropus alternus, see figure 270) the posterior legs, or 

 anal claspers, art- modified into long slender filaments, and in many 

 case-bearing caterpillars, e.g., Psychida and Eublemma scitula (see 

 figure 242) the prolegs, not being used for purposes of progression, 

 may he obsolescent or much modified. In the case of leaf-miners, 

 (e.g., Phyllocnistis citrella) the legs and prolegs may be entirely 

 absent, when the larva is said to be apodous (footless) ; but such 

 larvaa are necessarily so minute that they are not likely to come 

 under common observation. 



The structure and habits of caterpillars, sometimes even within 

 the same families, are often so modified or specialized in accordance 

 with food or habitat that it is difficult to classify them as a whole 

 in any satisfactory manner. But, if attention is confined solely to 

 those which do damage to growing crops, they may be placed in 

 groups of which the most important are borers in the stem, shoots 

 and roots, fruit-borers, leaf-eaters and leaf-miners. 



Fig. 60. — Injection Syringe foi wood-boring larvae. (Author's original pfa 



Boring caterpillars are found in almost every kind of crop and 

 attack various parts of the plant, although as a rule each different 



