2 THE LIFE-STORY OF INSECTS [CH. i 



of large, sub-globular, compound eyes are the most 

 prominent features. Below the head, however, may 

 be seen, now coiled up like a watch-spring, now 

 stretched out to draw the nectar from some scented 

 blossom, the butterfly's sucking trunk or proboscis, 

 situated between a pair of short hairy limbs or palps 

 (fig. 2). These palps belong to the appendages of 

 the hindmost segment of the head, appendages 

 which in insects are modified to form a hind-lip or 

 labium, bounding the mouth cavity below or behind. 

 The proboscis is made up of the pair of jaw-append- 

 ages in front of the labium, the maxillae, as they 

 are called. Behind the thorax is situated the abdo- 

 men, made up of nine or ten recognisable segments, 

 none of which carry limbs comparable to the walking 

 legs, or to the jaws which are the modified limbs 

 of the head-segments. The whole cuticle or outer 

 covering of the body, formed (as is usual in the 

 group of animals to which insects belong) of a horny 

 (chitinous) secretion of the skin, is firm and hard, 

 and densely covered with hairy or scaly outgrowths. 

 Along the sides of the insect are a series of paired 

 openings or spiracles, leading to a set of air-tubes 

 which ramify throughout the body and carry oxygen 

 directly to the tissues. 



Such a butterfly as we have briefly sketched lays 

 an egg on the leaf of some suitable food-plant, and 

 there is hatched from it the well-known crawling 



