1976] 
Parsons — Morphology of Corixidae 
139 
Figs. 8-10. Dorsal views; extent of exposed dorsal air stores indicated by stip- 
pling on left half. Fig. 8. D. zealandiae; exposed air stores on mesonotum (N II) and 
most of forewing. Fig. 9. M. sedula; exposed air store confined to anterior portion 
of embolium (E) and anteriormost part of claval suture (CS). Air on mesonotum is 
concealed by pronotum (N I). Fig. 10. H. interrupta; exposed air store on forewing 
more extensive than in Fig. 9 but much less extensive than in Fig. 8. Air on meso- 
notum mostly concealed by pronotum. 
15 pm in length, which are spaced too far apart (500-600 pm) to 
retain air. Only the embolium (E), the anteriormost part of the 
claval suture (CS), and the part of the wing beneath the pronotum 
(NI) have short hydrofuge hairs. On the embolium, which is less 
indented than in Hesperocorixa, they extend only as far posteriorly 
as the nodal furrow. The extreme lateral edge of the embolium 
bears short hairs only at the level of the mesothorax. Posterior to 
this level the lateral edge lacks hairs; at the nodal furrow they end 
approximately 80 ^m from the lateral edge. 
IV. Cervical Air Store 
In the Corixidae, unlike other Hydrocorisae, the posterior and 
lateral parts of the head are flattened and form flanges which over- 
lap the prothorax (Figs. 11-13). The cervical space is filled with 
air which is directly continuous with the ventral air store and is 
exposed to the water along the posterior edges of the head (Parsons 
1970). 
