140 THE WATER CABINET. 
some cases of an agreeable nature, and in others—as the 
common bed bug—of a most disgusting nature. The order 
readily separates itself into two great divisions—namely, 
the Geocorisa, or Land Bugs, and the Hydrocorisa, or 
Water Bugs. Both divisions supply a few specimens for 
the Water Cabinet, but the most important are those 
belonging to the second class. 
Among the first class in this order the most interesting 
is Hydrometra stagnorum, or the Water-measurer, which 
may be seen treading the surface of still brooks and rank 
pools in summer-time, in company with swarms of 
tipulidan gnats (Chironomi), whirlwigs, and two other 
aquatic bugs, the Gerris locustris and the Velia currens 
of Latrielle. The Hydrometra is a lively creature, a body 
so slender as to be little more than a black line half an 
inch in length, from which the long and angularly-jointed 
legs proceed in regular pairs. Under the microscope the 
divisions of the body are very plainly and prettily marked, 
and the terminal processes of the legs are made after the 
model of those water-shoes with which a certain clever 
Norwegian lately undertook to walk on water with nearly 
as much ease as on land. Whether the mechanician ever 
succeeded in this enterprise is not on record, but it is on 
record in the Book of Nature that this, and many other 
similarly-formed creatures, have found on the aqueous 
element a safe flooring for their feet ever since the first 
hour of creation, ere He who equipped them, had sent his 
Son to walk upon the waves. 
Notanecta and Nepa are of the same order, but are 
true water-bugs, formed for diving and sub-aqueous life, 
