526 
Psyche 
[September-December 
Acknowledgments 
Acknowledgment is made for the use of the scanning electron 
microscope in the Royal Ontario Museum, established through a 
grant from the National Research Council of Canada to the Depart- 
ment of Zoology, University of Toronto. We wish to thank John T. 
Polhemus, Randall T. Schuh, Fritz Plaumann, and D. T. Crisp, 
who provided specimens and/or data on habitats. We are also grate- 
ful to Eric Lin and Kian Chua for their technical help, to W. H. 
Thorpe and Thomas S. Parsons for their advice and encouragement, 
and to Donald A. Chant and the Department of Zoology, University 
of Toronto, who made available the laboratory facilities for this 
study. The investigation was made possible by a grant in aid of 
research to the senior author from the National Research Council of 
Canada. 
Summary 
The scanning electron microscope shows that in Cryphocricos 
barozzii and C. hungerfordi most of the ventral surface of the body 
and at least a part of the dorsal surface are covered with fine struc- 
tures which appear to be hydrofuge devices. Both surfaces bear short, 
fine hairs which are very similar to those of Aphelocheirus aestivalis , 
the only aquatic heteropteran in which plastral respiration has thus 
far been demonstrated. These hairs are much smaller and more 
densely-packed than those of Pelocoris fernoratus , which carries a 
large air bubble and relies upon atmospheric oxygen. On the ventral 
abdominal paratergites of Cryphocricos the plastral hairs are covered 
by curious, leaf-like, ridged setae which overlap each other and per- 
haps retain a “macroplastron”. Very elongated leaf-like setae occur 
on the six pairs of abdominal pressure receptors of Cryphocricos. 
A phelocheirus possesses leaf-like setae only on its single pairs of ab- 
dominal sense organs. The fourth through sixth abdominal sternites 
of Cryphocricos bear groups of microtrichia with a shingle-like ar- 
rangement; they resemble the plastral devices of some aquatic Cole- 
optera. These fine structural observations strongly suggest that Cry- 
phocricos has plastral respiration and utilizes dissolved rather than 
atmospheric oxygen. 
