556 



SCIENCE. 



[N. S. Vol. XXII. No. 566. 



species, has the bill forming about one 

 fourth of the total length. The species 

 of this genus, black and golden in color, 

 were very limited in range, and are now 

 nearly or quite extinct. Still another 

 group with sickle bills, Hemignathus, di- 

 verges from Vestiaria in having the upper 

 mandible only very long and decurved, the 

 loM^er one being relatively short, straight 

 and stiff. The numerous species are mostly 

 golden-yellow in color. Some or all of 

 them use the lower mandible for tapping 

 the trees, after the fashion of woodpeckers, 

 while with the long and flexible upper one 

 they reach into cavities for insects or in- 

 sect larvae or suck the honey of flowers. 

 The group contains long-billed forms like 

 Hemignathus procerus of Kauai, in which 

 the bill is more than one fourth the total 

 length of the bird, and short-billed forms 

 like Hemignathus or Heterorhynchus 

 olivaceus of Hawaii. In the short-billed 

 forms the two mandibles are most unlike; 

 the upper very slender, much curved and 

 about one fourth the length of the rest of 

 the body, the lower mandible half as long 

 and thick and stiff. These birds feed 

 chiefly on insects in the dead limbs of the 

 koa trees in the mountain forests. 

 Mr. S. B. Wilson remarks: 



Nature has shown great symmetry in regard to 

 the species of this genus {Hemignathus) to be 

 found in the Sandwich Archipelago, three of the 

 main islands having each a long-billed and a 

 short-billed form. 



This of course is most natural. Both 

 long-billed forms (Hemignathus) and short- 

 billed forms {Heterorhynchus) have spread 

 from the island where they were originally 

 developed to the other islands, each chang- 

 ing as it is isolated from the main body of 

 the species and subjected to natural selec- 

 tion under new conditions. 



With the genus Hemignathus and its 

 aberrant section, Heterorhynchus, the 



forms with slender bills reach their culmi- 

 nation. 



Going back to the original stock, to which 

 Oreomystis hairdi is perhaps the nearest 

 living ally, we note first a divergence in 

 another direction. In Bhodacanthis, the 

 bill is stout like that of the large finch, not 

 longer than the rest of the head, and 

 curved downward a little at the tip. The 

 species of this genus feed largely on the 

 bean of the acacia and other similar trees, 

 varying this with caterpillars and other 

 insects. The stout bill serves to crush the 

 seeds. In Chloridops, the bill is still 

 heavier, very much like that of a grosbeck. 

 Chloridops kona is, according to Mrs. 

 Robert Perkins, a dull sluggish solitary 

 bird and very silent, its whole existence 

 may be summed up in the words 'to eat.' 

 Its food consists of the fruit of the aaka 

 (bastard sandal tree), and as they are 

 very minute, its whole time seems to be 

 taken up in cracking the extremely hard 

 shells of the fruit, for which its extraor- 

 dinarily powerful bill and heavy head have 

 been developed. 



The incessant cracking of the fruits, when one 

 of these birds is feeding, the noise of which can 

 be heard for a considerable distance, renders the 

 bird much easier to get than it otherwise would 

 be. Its beak is always very dirty with a brown 

 substance adhering to it which must be derived 

 from the sandal-nuts. 



In Psittirostra and Pseudonestor the bill 

 suggests that of a parrot rather than 

 that of a grosbeak. The mandibles are 

 still very heavy, but the lower one, as in 

 Heterorhynchus, is short and straight, 

 while the much longer upper one is hooked 

 over it. Pseudonestor feeds on the larvge 

 of wood boring beetles {Clytanus) found 

 in the koa trees (Acacia falcata), while the 

 closely related Psittirostra eats only fruits, 

 that of the ieie (Freycinetia arhorea) , and 

 the red mulberry (Morus sapyrifera) be- 

 ing especially chosen. In all these genera 



