510 The Philippine Journal of Science 1923 



group, particularly to Mr. R. C. McGregor, Mr. M. H. Curran, 

 Mr. Edward H. Taylor, and Dr. A. W. C. T. Herre. 



I am well aware that, in many instances, it is difficult to 

 recognize a certain species even from a good description, par- 

 ticularly in such genera as Pachyrrhynchus and Metapocyrtus. 

 In order to eliminate the difficulties in this respect and to pre- 

 vent errors of misinterpretation of known species in the future, 

 I consider it essential to give good illustrations of all species 

 as far as possible. All the original drawings, with the excep- 

 tion of Plate 8, 2 have been made by myself. 



This, the first part of my paper, treats of the genus Pachy- 

 rrhynchus, and it is hoped to deal with the other genera in sub- 

 sequent parts. 



All the Philippine representatives of this group are found in 

 localities which have a rather rich tropical vegetation. Favored 

 localities are rather open, mixed forests with a dense under- 

 growth along rivers and ravines or on ridges and mountains. 

 Most species are found in such localities on the smaller trees, 

 bushes, shrubs, or ferns. Not a single species is known to feed 

 on any strictly cultivated plant. Pachyrrhynchus orbifer Wa- 

 terh. is found in Luzon (Ilocos Norte and Kalinga Provinces) , 

 sometimes in very large numbers, on one of the Euphorbiacese, 

 Jatropha curcas Linn, (physic nut). This is a naturalized 

 plant in the Philippines, which is found in a semicultivated 

 " stage, and is used by Filipinos as fish poison. Whether or not 

 P. orbifer actually feeds on this plant I am unable to say. Rel- 

 atively few species are found in the lowlands ; if they do occur 

 there, such localities are mostly spurs or low ridges which are 

 really terminations of some mountain range. By far the larger 

 number of species is found in mountain regions between 500 and 

 2,000 meters altitude. Because of the large percentage of spe- 

 cies found in the central and northern parts of Luzon, it seems 

 probable that the picturesque and little-explored mountainous 

 district between 16° and 18° north latitude was the center of 

 dispersal of the pachyrryhnchids or is the region in which they 

 originated. Details concerning their general distribution are 

 given farther on in this paper. In northern Luzon more than in 

 any other island of the group a greater diversity of genera as 



' I wish to express again my thanks to Prof. K. M. Heller, of Dresden, 

 who kindly assembled the specimens for Plate 8 and secured the services 

 of Mr. Max Bohme for drawing it. Plates 7, 8, and 9 will be published 

 with the conclusion of this part. 



