138 
Psyche 
[June 
In all three corixids the exposed ventral surfaces of the prothorax 
and pterothorax are covered with densely distributed short hairs. 
Although long hairs are also present on the thorax, they are usually 
farther apart than on the abdomen and are entirely absent in some 
areas. Long hairs are rarer on the ventral thorax in Diaprepocoris 
than in the other two insects, and they are shorter than those on 
the abdomen. In Corixa (Corixinae; Thorpe 1950) and Hespero- 
corixa, however, the thoracic long hairs are longer than the ab- 
dominal ones. The ventral thoracic air layer is easily visible in 
living Hesperocorixa (Parsons 1970); the presence of hydrofuge 
hairs on the ventral thorax of the other two corixids indicates that 
they possess a similar, although perhaps thinner, air store in this 
region. 
III. Supra-alar Air Store 
In Diaprepocoris almost all of the exposed surface of the fore- 
wing bears hydrofuge hairs (Fig. 8, stippling on left). The clavus 
(CA), corium (CO) and membrane (MB) are covered with densely- 
packed short hairs which extend nearly to the lateral edge of the 
wing. The clavus and corium also bear long hairs which are 20 to 
30 pm apart (Fig. 2). The extreme lateral edge of the corium lacks 
hairs, the bare strip being widest (approximately 0.2 mm) posterior 
to the nodal furrow (Fig. 8, F). The embolium (E), unlike that of 
the other two corixids, is not sharply differentiated from the rest 
of the corium and is indented only anteriorly, approximately half 
way to the nodal furrow. 
In Micronecta (Fig. 9) and Hesperocorixa (Fig. 10) the em- 
bolium is .more sharply differentiated and most of the exposed 
surface of the forewing lacks hydrofuge hairs. Living specimens 
of Hesperocorixa have an air layer (Fig. 10, stippling on left) on 
the strongly-indented embolium, on the anterior part of the claval 
suture (CS) and on the portion of the clavus which is overlapped 
by the pronotum (N I) (Parsons 1970). All these regions have a 
pruinose texture and are covered with short hairs and occasional 
long ones in Hesperocorixa. The hairs on the embolium extend 
well posterior to the nodal furrow. Anterior to the furrow they 
reach to the lateral edge of the wing, but posterior to the furrow 
they end a short distance medial to the lateral edge. 
Micronecta has an even less extensive supra-alar air store (Fig. 9, 
stippling on left). The corium and clavus bear thick setae, up to 
