THE REDUVIUS PERSONATUS. 375 
flies about the fields, returning, however, to houses in order to 
lay its eggs. 
A larva may be seen in the engraving on the ground, close to 
the basket on the right hand side ; the perfect insect is entering 
the house, and immediately beneath it, on the ground, is a nymph. 
The Hydromelridce are aquatic Reduviincs. They are insects 
which are commonly observable during the summer upon the 
the metamorphoses of Reduvins persoiiatus. 
surface of running or standing waters. Some have long narrow 
legs, with which they appear to be taking the measure of the top 
of the water. They are called Hydrometra stagnorum. The 
species of the genus Gerris , which are very numerous, are also very 
common, and some others belonging to the genus Halobates have 
been found walking over the waves of the tropical seas as easily 
as the first twirl and twist about on our ponds. In order to enable 
a Gerris to live on the surface of stagnant water, and to skim upon 
