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Psyche 
[Vol. 95 
Figure 1. Terminal abdominal structure in Laccornis and Hydrovatus. 
A) Dorsal view of terga 6-8 of Laccornis difformis (40X) B) Dissected abdominal 
apex of L. difformis (40X). Tergum 8 is folded back (all the way to the left) so that 
ventral surface is exposed revealing ventral fold (indicated by arrow); tergum 8 is not 
bilaminar. C) Acutely pointed eighth tergum of Hydrovatus pustulatus (80X). 
D) Dissected abdominal apex of H. pustulatus. Tergum 8 is folded so that dorsal 
lamina (left arrow) is separated from ventral lamina (right arrow) (60X). 
The anterior edge of tergum 7 (Fig. 2C) is expanded anteriorly as 
a broad, bisinuate flange with a short anterolaterally extended apo- 
deme at each anterolateral corner. Apodemes of tergum 7 extend 
anteriorly for 75 per cent of the length of tergum 6. 
The function of the modified methline abdominal structures has 
not been observed. Ovipositional function is ruled out because mod- 
ifications are identical in males and females. Perhaps, the acutely 
pointed and sclerotized apex is a device for puncturing plant tissue 
to obtain trapped air. It is interesting that a similar behavior has 
