177 
1976] Parsons — Morphology of Corixidae 
PT Posttergite 
S Spiracle or spiracular trachea 
SA Attachment of scolophore 
SC Sclerite of mesothoracic scolopophorous organ 
SO Site of scolopophorous organ 
SS Sclerotized strip 
ST Sternite 
SV Sieve-plate of metathoracic spiracle 
T Tergite 
TAM Functional thoracic-abdominal membrane 
TAS Thoracico-abdominal sclerite 
V Ventral region of mesothoracic epimeron or metathoracic 
episternum 
W Wing-anchoring ridge or groove of metathoracic epister- 
num 
WS Setae on lateral edge of forewing 
X Xiphus of metathoracic sternum 
2PH, 
3PH Second phragma, third phragma 
II-III Lateral boundary between mesothorax and metathorax 
Acknowledgements 
Special thanks are due to Mrs. Rosemary Hewson, who took 
all the scanning electron micrographs for this project. I also wish 
to thank Mr. Ivor Lansbury, Dr. Syoiti Miyamoto, Dr. Isabelle 
Sprague, and Dr. Vida Stout for providing specimens, Dr. Curt 
Dunn for identifying the species of Diaprepocoris, Dr. Aleksander 
Wroblewski for information on Micronecta, Mr. Eric Lin for his 
technical help, Dr. Thomas Parsons for reviewing the manuscript, 
and Dr. David Mettrick, Chairman of the Department of Zoology, 
University of Toronto, for providing the laboratory facilities for 
the investigation. Acknowledgement 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 Department of Zoology, University of Toronto. 
The investigation was made possible by a grant in aid of research 
from the National Research Council of Canada. 
