432 



migratiiig- birds, or higli winds or ocean enrrents to account 

 for the arrival here of such delicate insects. 



Bird niiorations hither are mostly, if not entirely, from 

 America, and the Hawaiian jumping plant lice and leaf hop- 

 pers do not seem to have come from there. Windstorms sel- 

 dom, if ever, blow from present land areas of the South Pacific 

 to tlu^se Islands, nor do ocean currents come this way from that 

 part of the world. However, we must consider that not more 

 than one ancient immigrant of the Psyllidae and probaldy only 

 three or four of leaf hoppers succeeded in establishing them- 

 selves here during several million years. It must be admitted 

 that what now seems impossible might have succeeded by chance 

 once in a million years. It is conceivable that once in several 

 million years a windstorm might have carried a leaf with galls 

 containing nymphal psyllids and dropped the leaf in an Ha- 

 waiian forest of the same kind of trees — an exceedingly rare 

 chance ! — whereupon the insect might establish itself. Another 

 psyllid species has been a less ancient immigrant, but how it 

 arrived or when it is not possible even to surmise. This one 

 apparently has not given rise to other species than one which 

 now lives on the native palms, but nevertheless seems to have 

 arrived a long time ago. 



The fTu:MPixa Pi.ant Lice. 

 Psyllidae, or Chermidae (Ilomoptera). 



The jumping plant lice (Psyllidae or Chermidae) consti- 

 tute a family of the homopterous sucking bugs, being allied to 

 the true plant lice and scale bugs and also to the leaf hoppers 

 and lantern flies. They are small insects, from 1-32 to 1-4 

 inch in length, with four wings, the third pair of legs usually 

 developed for leaping from which habit the first part of their 

 popular name has been derived. Their superlcial resemblance 

 to true plant lice (Aphididae) has suggested the latter part of 

 their name. 



The psyllids live by sucking the juice from plants by 

 means of their slender, pointed beak which arises from the 



