Bugs, Cicadas, Aphids, and Scale-insects 
199 
for some time under water. Both kinds are attracted to lights, and may 
often be seen in summer about outdoor electric lamps. The eggs of the 
water-boatmen are attached to the submerged stems of aquatic plants, while 
those of the back-swimmers are inserted in the stems, the female having 
a sharp ovipositor for this purpose. In winter the adults lay dormant in the 
mud at the bottom of ponds or streams. 
All the species of water-boatmen in the country belong to the genus 
Corisa, while there are three genera of back-swimmers, Notonecta, with 
hind legs longer than the others and fore wings but little longer than the 
abdomen, being the most abundant and 
wide-spread. Plea is a genus with all the 
legs alike, while Anisops, the third genus, 
has the wing-covers usually much longer 
than the abdomen. The complete life- 
history of no member of either of these 
families of water-bugs is yet known, but it 
ought not to be a difficult matter for some 
persistent observer to add this needed 
knowledge to entomological science. Both 
water-boatmen and back-swimmers live 
readily in aquaria, and make thoroughly interesting creatures to observe 
at leisure. The characteristic habits of obtaining air, swimming, capturing 
prey, etc., can all be learned from the observation of aquarium specimens. 
The capacity of the water-boatmen to remain below the surface in pure 
water for protracted periods, apparently indefinitely long, needs to be better 
understood than it is at present, and should be an interesting problem for 
some observer of aquarium life. 
Creeping or crawling about among the stems and leaves of submerged 
plants in reedy and grassy quiet waters, and feeding on smaller insects, may 
sometimes be found certain small flat-bodied oval insects with front legs 
thickened and fitted for grasping. These are water-creepers, or Naucoridae, 
only five species of which are known in this country. The single species 
found in the eastern states is known as Pelocaris jemorata, and is about 
J inch long, broadly oval in shape, and yellowish brown in color. The 
other species belong to the genus Ambrysus and are restricted to the western 
states. The life-history of no member of the family is known. 
Occasionally there will be seen resting, or swimming slowly about, at the 
bottom of the pool a veritable giant bug, 2} inches long and ij inches wide, 
with heavy strong legs flattened and oar-like and the front ones held out 
arm-like and bent in an expectant grasping position. Again, in the warm 
sultry evenings of midsummer and early autumn, among the swarms of 
insects attracted to the electric lights on the streets, one or two great bugs 
Fig. 274. —A water-boatman, Corisa 
sp. (After Jenkins and Kellogg; 
twice natural size.) 
