268 NATURAL HISTORY OF ARTHROPODS. 



backwards. The bucciiloe, antepectus, and base of the two posterior pairs of coxae are 

 pale ouhreous ; the corresponding thighs and shanks are dark tan-color. A narrow 

 stripe, composed of gray streaks, interrupted by black dots, extends along the middle 

 of the tergum ; and the outer edges of the connexivum are tau-brown, raised and 

 marked with a sericeous spot in the angle of each incisure. The terminal segments 

 are usually also tan-brown. In fresh specimens, the whole upper surface is invested 

 with minute, bronze pubescence, and the sericeous plush is continued in an interrupted 

 stripe on the upper side of the two posterior pairs of coxa3. The processes which 

 terminate the abdomen are acute, and extend to about the tip of the first genital 

 segment, while the sides of the last abdominal segments are a little waved in the 

 female, but oblique in the male, and deeply concave on the middle. The species 

 measures a half-inch, or rather more, to the end of the venter. This, like many of 

 its congeners, is an excessively active and conspicuous insect on all our brooks and 

 streams of water. It moves rapidly by rowing with the long, slender, and hairy hind 

 legs, and is generally seen in small groups on the quiet parts of the waters. The 

 depth of color and degree of wrinkling of the back of the mesothorax dejaend much 

 upon the maturity and vigor of the individuals ; the heavier and coarser ones, being 

 the stronger, have a thicker integument, while the more delicate presei-ve the paler 

 colors, and often clearer markings. 



These insects stow themselves away under the banks of streams, in the mud 

 beneath leaves or rubbish, or at the bottom of water under stones and roots of trees 

 when the autumn begins to be cold, and from thence they reajjpear upon the surface of 

 the water as soon as the warm weather of spring returns. Soon after this the eggs 

 are attached by a sort of glue to the leaves and stems of aquatic plants. They are 

 whitish translucent, long, cylmdrical, more blunt at the end from which the young 

 emerges than ^ at the somewhat tapering, but round, opposite extremity. If the 

 weather contiimes to grow warmer, these eggs mature in about two weeks ; then the 

 larvae push their way out, not, as in many other Heteroptera, by thrusting up the lid, 

 but by bursting through a slit which opens a little way down the side. Numei-ous 

 other species inhabit this country, and resemble those of Europe in the general plain- 

 ness of their brown suits and slight ornamentation; but in the East Indies the forms 

 are often bright yellow, and adorned with dark marks and stripes. 



Our smaller species, which are common on the pools, ponds, and water in swamps 

 and ditches, have mostly a dark, fuscous or blackish-olive ground color, bordered with 

 yellow on the sides of the abdomen, and belong to the genus LimnotrecJms. These 

 have the carinate line on the dorsum of the thorax very distinct and unbroken. Some 

 of these latter have a wide distribution, being found far north on the waters of 

 Great Bear Lake, and from thence extending southward to New Mexico and Texas. 

 On the eastern side of the continent L. marginatus may be found from Maine to 

 Georgia. A very pretty, highly polished, black species, margined and striped above 

 with yellow, but pale yellowish beneath, and with pale, fulvous legs, the Limnometra 

 marginata, inhabits southern Florida, the Antilles, and eastern Peru. It lives on the 

 quiet parts of the streams in Cuba and San Domingo, and is closely related to one or 

 two species inhabiting the Philippine Islands. About fifty species belonging to this 

 part of the family have already been discovered, of which the greater number thus 

 far described have been captured in Europe and Asia. The American forms have 

 been much neglected, and scarcely more than half a dozen have been recorded as from 

 the United States. 



