1912] Aquatic Hymenoptera in America. 69 
In three cases we observed males and females apparently in 
copulation under water on the stems of the plants. We have 
not had opportunity to observe oviposition although females 
have been seen several times attempting to insert the ovipositor 
in the eggs of Notonecta which were nearly ready to hatch. 
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Fic. 2. Caraphractus cinctus Walker. 
Drawn from life by Miss Anna C. Stryke. 
We have been unable to see any external air supply carried 
by these insects while under water. While submerged they 
appear to be perfectly wet but as soon as they emerge into the 
air they seem to be perfectly dry. They are able to live sub- 
merged in water for over 12 hours in a bottle filled full of water 
and corked. 
Fic. 3. Egg of Caraphractus cinctus Walker. 
