ARTHROPODA. 



205 



their curved sucker or proboscis and four scaly wings. 

 The sucker is formed by the modification and union 

 of the first pair of appendages, called maxillse, while 

 the other appendages of the mouth are but slightly 

 developed : the butterflies are thus adapted for their 

 mode of feeding, which consists in sucking honey (see 

 fig. 61). They present the typically complete meta- 



Fiff. 60. — Suctorial proboscis of a butterfly, formed by the junction of the 

 maxilto (Jfa:). (Prom Ulaus and Sedgwick, after Savigny.) 



morphosis of insects. The cocoon-spinners (Bom6?/cma) 

 include the Silkworm. Some of the spinners are 

 social, and build a nest in common, as do also the 

 caterpillars of some moths, e.g. Little Ermine-Moth 

 {Ypunomeuta), Brown-tail Moth, etc. The social 

 forms would seem to have the germ of that colonial 

 instinct which produces such remarkable results 

 among the ants and bees. In the Processional- 

 Caterpillars of Southern Europe {Onethocamjpa pro- 



