INSECTA. 



253 



B|be ox. The fleas form a modified type of the Diptera^ 

 with the wings reduced to mere rudiments, a loss of motor 

 organs characteristic of parasites. 



Order IV. — Lepidoptera, 



The metamorphosis is complete. The mouth parts are 

 adapted for "sucking," and there are two pairs of large 

 opaque wings which are covered with minute scales. In 

 this order are included the " butterflies " and " moths.'* 

 The mouth parts are much modified. The mandibles are 

 mere vestiges, and the maxillae are produced into a long 



Fig. 174.— The Cabbage White (/'/^rzV hrassiccE). 



Female depositing eggs, larva (caterpillar), and pupa. 



spirally-coiled *' proboscis," composed of two half-cylinders 

 apposed together. The labium is small and bears a pair 

 of fairly large labial palps ; the maxillary palps are vestigial. 

 In use the proboscis is uncoiled and thrust into flowers, 

 nectar being sucked up its interior. 



The wings are covered with minute scales of varying 

 shape which are easily rubbed off" when the membranous 

 wing is exposed. As a general rule butterflies or moths 

 have bright colours on the upper surface of the wingSj'and 

 sombre protective colours below {cf. Chap. IX.). 



The larva is a "caterpillar" which often executes great 

 destruction amongst plant-life. 



