THE CLASSIFICATION OF INSECTS 175 



primitive species of moths, are extraordinarily modified so as 

 to form a long, slender, flexible, sucking tube, by means of which 

 flower nectar and water can be drunk. This tube is made of 

 the two elongated maxillae, grooved on their inner faces and 

 held, even locked, together to form a perfect tube. Upper lip, 

 mandibles, and under lip are either wholly wanting or reduced 

 to mere rudiments. Thus no adult moth nor butterfly can 

 seriously injure any plant or animal; but strongly contrasted 

 to this innocuousness of the adults are the serious capacities 

 for mischief of the larval or caterpillar stage. 



From the eggs, which are almost always deposited on the 

 proper special food plant, hatch the well-known worm-like 

 larvae or caterpillars which are provided with strong biting 

 mouth-parts. They proceed at once to the serious business of 

 voracious eating. The young caterpillar may eat many times 

 its weight of leaf tissue in a single day, and where the cater- 

 pillars are abundant they may quickly defoliate whole shrubs 

 and trees. The caterpillars are provided with three pairs of 

 jointed thoracic legs and five pairs of fleshy unjointed abdominal 

 legs, and can migrate freely from plant to plant, thus increasing 

 their capacity for harm. When they are full grown they usu- 

 ally burrow into the ground, spin a silken cocoon, or seek some 

 hiding place in which to pupate. The pupa is enclosed in a 

 thick, horny, chitinized cuticle, and is wholly inactive and 

 takes no food. When the radical changes of the breaking 

 down of the larval organs and the building of the new organs 

 of the adult are completed, the cuticle breaks and the winged 

 imago emerges. 



The food habits of the caterpillars make many of them 

 serious pests of growing crops. Most are leaf eaters, and all 

 are voracious feeders, so that an abundance of cut-worms or 

 army-worms or tomato-worms always means hard times for 

 their favorite food plants. Some kinds do not eat leaves but 

 attack fruits, as that dire apple pest, the codling-moth larva; 

 while still others are content with dry organic substances, as 

 the larvae of clothes-moths, meal-moths and the like. The sole 

 material compensation which the Lepidoptera make for their 

 disastrous toll on all green things is the gift of silk made by the 



