146 
Psyche 
[June 
which bends anteriorly forms a short projection internally (II-III); 
this flap, which is similar to the intersegmental projection of Aphelo- 
cheirus (Aphelocheiridae; Parsons 1974), partially conceals the 
base of the metathoracic spiracular trachea. The metathoracic 
spiracle (Figs. 15 and 18, S III) lies immediately below the scolopo- 
phorous organ in the dorsal part of the mesothoracic epimeron, 
immediately anterodorsal to the intersegmental boundary. The 
fine structure of the spiracle and sense organ are described on 
pp. 161 and 164. 
Unlike Micronecta and Hesperocorixa, Diaprepocoris possesses 
a lateral epimeral ridge, which runs from the wing-anchoring knob 
to the postalar region (Fig. 15, LR). The ridge is much less pro- 
nounced than its homologue in typical Hydrocorisae (Fig. 14A) 
and, unlike the latter, is not high enough to conceal the metathoracic 
spiracle externally or to create a lateral intersegmental air space. 
Thus the spiracle, like those of Micronecta and Hesperocorixa, 
opens directly onto the subalar air space. 
Nm som PLm hw jsoe fw nh 
Fig. 15. D. zealandiae; lateral view of pterothorax and anterior abdomen. 
Wings and coxae removed. 
