142 
Psyche 
[June 
VI. Subalar Air Store 
In all three insects the forewings are fully developed and extend 
to the tip of the abdomen (Figs. 11-13). All the Hesperocorixa 
examined had fully developed hindwings (Fig. 13, HW) and flight 
muscles. All specimens of the other two corixids, however, had 
vestigial indirect flight muscles and short hindwings. The latter 
extended to the level of the fourth and fifth abdominal tergites in 
Diaprepocoris and Micronecta respectively. 
Hesperocorixa, like most Hydrocorisae, carries air beneath the 
forewings. The large subalar air store is exposed along the edges 
of the forewings posterior to the level of the mesothoracicepimeron, 
and the amount of exposure is increased when Hesperocorixa bends 
the abdomen ventrally on the thorax (Parsons 1970). 
Leong (1961) reported the presence of a subalar air store in Micro- 
necta sp., and Diaprepocoris almost certainly possesses one. The 
scanning electron nr.croscope shows that in both insects the ventral 
surfaces of the clavus and corium bear short, densely-packed hydro- 
fuge hairs. In these two insects the ventral margin of the forewing 
(Figs. 5 and 6, FW) projects laterally, beyond the edge of the body, 
as far posteriorly as the anterior abdominal segments. The short 
hydrofuge hairs extend onto the exposed, ledge-like ventral edge 
of the wing in both insects. In Micronecta they extend all the way 
to the lateral edge, while in Diaprepocoris they cover only the medial 
half of the exposed portion. 
In Hesperocorixa the ventral edge of the wing does not project 
as far laterally as in the other two corixids. At the level of the meta- 
thorax the extreme dorsolateral edge of the embolium bears a 
patch of very long, curved setae (Figs. 10 and 13, WS), and immedi- 
ately ventral to the posteriormost setae there is an extensive gap 
between the edge of the wing and the edge of the body (Fig. 13, 
arrow). In living specimens the subalar, supra-alar, and ventral 
air stores communicate with each other along this gap and for some 
distance posterior to it (Parsons 1970). The subalar and ventral 
abdominal air stores also appear to communicate with each other 
along the posterolateral margins of the abdomen, which bear long 
setae (Fig. 7, right side of figure). 
The amount of communication between the subalar and supra- 
alar stores cannot be determined in the other two corixids without 
living specimens. Like Hesperocorixa , however, both Diapre- 
pocoris and Micronecta possess a large space between the fore- 
