160 
Psyche 
[June 
along its entire length; the dorsal portion, which is concealed by 
the wing, is convex anteriorly but deeply recessed posteriorly (C). 
The recessed portion lies closely against the inner wall of the lobe, 
and the apposed surfaces of the two walls (“vertical plate” of Par- 
sons 1970) become secondarily fused in mature specimens. 
Because of the close apposition of the two walls, the full extent 
of the dorsal opening into the lobe is visible only in newly-moulted 
insects. As in Micronecta, the opening extends posteriorly as far 
as the base of the abdominal muscle process (Fig. 24, MP). An 
earlier publication (Parsons 1970) has described how the posterior 
part of the opening becomes secondarily closed off in mature 
specimens. 
Fig. 24. H. interrupta; semi-diagrammatic lateral view of thoracico-abdominal 
region, prepared as in Fig. 21. Heavy black dot indicates position of coxal process; 
heavy dotted line indicates dorsal edge of inner wall of metathoracic epimeral lobe 
(EML). Head of arrow indicates position of first abdominal spiracle (removed) in 
thoracico-abdominal membrane (TAM); spiracle communicates with ventral air 
store (white arrow) and with supra-alar air store. 
