IV 
Contents 
No. 4, April, 1921 
[Issued July 5, 1921.] 
Page. 
Perkins, Granville A. The structure of the electron 325 
Perkins, Granville A. Absolute units and the relativity principle.. 341 
Fisher, W. S. New Coleoptera from the Philippine Islands. Family 
Buprestidas, tribe Agrilini 8i|J|gS 349 
Haughwout, Frank G. A case of human coccidiosis detected in the 
Philippine Islands, with remarks on the development and vitality 
of the cysts of Isospora hominis (Rivolta) 449 
Four plates and one text figure. 
No. 5, May, 1921 
[Issued July 14, 1921.] 
Valencia, F. V. Mechanical tests of some commercial Philippine 
timbers 485 
One plate and nineteen text figures. 
McGregor, Richard C. Birds of Antique Province, Panay, Philip- 
pine Islands 537 
Two plates. 
Kieffer, J. J. Chironomides des Philippines et de Formose 557 
Saccardo, P. A. Fungi Sinensis aliquot a cl. Prof. Otto A. Rein- 
king collecti et communicati 595 
Karny, H. H. Katydids (Tettigonioidea) of the Philippine Islands, 
collected by C. F. Baker 607 
No. 6, June, 1921. 
[Issued September 15, 1921.] 
West, Augustus P., and Montes, Zoila. The composition, solubility, 
and oxidation of lumbang oil 619 
Three plates. 
Morrison, Harold. Some nondiaspine Coccidse from the Malay 
Peninsula, with descriptions of apparently new species 637 
One plate and thirteen text figures. 
Funkhouser, W. D. New genera and species of Philippine Mein- 
bracidse 679 
One plate. 
Rohwer, S. A. Some Philippine wasps of the family Chrysididae.... 691 
Peschet, R. Description d’un Canthydrus (Coleoptera Dytiscidae) 
nouveau, des lies Philippines 693 
Nanagas, Juan C. Position and size of the kidneys among Filipinos.. 695 
Three text figures. 
Garcia, Arturo, and Solloza, Juan. Length and position of the 
vermiform appendix in Filipinos - 707 
One text figure. 
Spaeth, Frank. Philippine and Bornean species of Hoplionota 
(Coleoptera) .■. 721 
Reviews 733 
Index |p! I. 735 
