258 ARTHROPODA [CH. 



described is far greater than that of Flies. Amongst the commoner 

 genera are the Gnats and Mosquitoes, Gulex ; the Daddy-long-legs, 

 Tipula-, the Gall-fly, Cecidomijia (Fig. 112) ; the Horse-fly, Tabanus; 

 the Bot-fly, Oestrus; the common House-fly and Blue-bottle, Musca, 

 and many others. 



Order XIII. Siphonaptera. 



The Fleas, of which the commonest is termed Pulex irritans, are 

 wingless but endowed with considerable powers of jumping. They 

 were formerly classed with the Diptera, but are now regarded as 

 a type of a separate order, the Siphonaptera (sometimes called 

 Aphaniptera). 



In the Fleas the mandibles form stylets with saw -like edges and 

 there is a short hypopharynx. The maxillary palps are long but the 

 basal portions of these appendages are broad and triangular and 

 not converted into stylets. The labial palps are very long and 

 grooved and form sheaths for the mandibles and the hypopharynx. 

 The metamorphosis is complete, the larva is worm-like and lives on 

 animal refuse. The body of the adult is much compressed from 

 side to side, which is an unique feature among Insects. 



Order XIV Lepidoptera. 



The Lepidoptera (Gk. Ac?'?, a scale, irrepor, a wing) have mouth- 

 parts adapted for sucking only. The two pairs of wings are similar 

 in appearance and covered with scales (flattened spines) which give 

 rise to the beautiful pattern on the wings but are easily rubbed off. 

 None of the wings fold up and when not in use are either held 

 erect or are depressed on each side of the body. The metamor- 

 phosis is complete. 



This order is very clearly defined and the members show a 

 marked resemblance one to another. It includes the Butterflies 

 and Moths, and all of them exhibit a very definite and complete 

 metamorphosis. The eggs give rise to worm-like larvae known as 

 caterpillars, which consume much food, generally of a vegetable 

 nature (Fig. 102). After a considerable time, varying from a few 

 weeks to three years, the caterpillar comes to rest, and in such 

 cases as the Silk-worm Moth, Bombyx mori, surrounds itself by a 

 case or cocoon spun by itself, which famishes the material silk 

 (Fig. 103). Within this cocoon, or in some species without forming 

 a cocoon, the caterpillar forms a pupa, and whilst in this state it 



