238 THE INSECTS 



be given to this order of insects. The long proboscis, a sucking 

 tube through which the insect sucks nectar from flowers, is an- 

 other character by which the Lepidoptera may be known. 



Life History. The monarch or milkweed butterfly (Anosia 

 plexippus) is one of our commonest insects. Its orange-brown, 

 black-veined wings are familiar to every boy or girl who has been 

 outdoors in the country during the fall months. The adult female 

 lays her eggs in the late spring on the milkweed. The eggs, tiny 

 sugar-loaf-shaped dots a twentieth of an inch in length, are fas- 

 tened singly to the underside of milkweed leaves. Some won- 

 derful instinct leads the animal to deposit the eggs on the milkweed, 

 for the young feed upon no other plant. Eggs laid in May hatch 

 out in four or five days into rapid-growing caterpillars, each of 

 which will molt several times before it becomes full size. These 

 caterpillars possess in addition to the three pairs of true legs, 

 additional pairs of prolegs or caterpillar legs. The animal at this 

 stage is known as a larva. 



Formation of Pupa. After a life of a few weeks a.t most, the 

 caterpillar stops eating and begins to spin a tiny mat of silk upon 

 a leaf or stem. It attaches itself to this web by the posterior pair 

 of prolegs, and there hangs until a last molt (which occurs within 

 twenty-four hours after attachment) gives the animal the form it 

 assumes in the stage known as the chrysalis or pupa. 



The Adult. After a week or more of inactivity, the exoskeleton 

 is split along the dorsal side, and the adult butterfly emerges. At 

 first the wings are soft and much smaller than in the adult. Within 

 fifteen minutes to half an hour after the butterfly emerges, however, 

 the wings are full-sized, having been pumped full of blood. 



In the adult form the animal may survive the winter. The 

 milkweed butterfly is a strong flyer, and has been found over five 

 hundred miles at sea. They may migrate southward upon the 

 approach of the cold weather. Some common forms, as the 

 mourning cloak (Vanessa antiopa), hibernate in the North, passing 

 the cold weather under stones or overhanging clods of earth. 



Comparison between a Moth and a Butterfly. The big electric light 

 moth cecropia (Samia cecropia) is an insect familiar to most of us. In 

 general it resembles a butterfly in structure. Several differences, however, 

 occur. The body is much stouter than that of the butterfly. The wings 



