184 



CATERPILLAR PESTS. 



caterpillars grow to more than one incli long-, many species never 

 exceeding 1 half an inch in length. When the body is not hairy but 

 somewhat transparent, the caterpillars are often greenish from the colour 

 of the food in the alimentary canal ; or they are opaque green, brown, or 

 variously striped and marked. Many are hairy, spiny and provided with 

 horns and excrescences. 



The duration of larval life varies with the different species : some 

 are full fed in a week, others only after two to three weeks or longer. 

 From two to three weeks is the most general length of the larval life. 

 These caterpillars have regular daily habits which must be considered 

 in the adoption of remedies ; many feed only in the morning and even- 

 ing, hiding away in the soil during the middle of the day ; others feed 

 principally at night or are to be found on the plant only in the early 

 morning and late evening. 



If food is plentiful they feed regularly and voraciously until they are 

 full grown, when they turn to chrysalides. Before doing this they 

 hide away, some making cocoons on the plant or in the soil, others enter- 

 ing the soil and making cells there, others again twisting over the leaf 

 and thus making themselves a shelter. Butterfly caterpillars hang them- 

 selves to the plant or bend over a part of the leaf. 



Fia. 213. 

 A Semi-looper Caterpillar, the first pair of sncTcer-feet reduced. 



The period of pupation is determined by climatic conditions, and 

 may be short, as in the rains, or prolonged through the cold weather and 

 succeeding dry hot months until the next rains. Hibernation is the 

 rule, and whilst some emerge as moths or butterflies at the close of 

 the cold weather, the majority emerge only in the rains. The first brood 

 appearing in April would be followed perhaps by a second in June, a 

 third in August and the last in October ; more usually there would be p, 



