BUGS. 273 



longer membrane. The largest and best known species is the V. rivulorum of Europe. 

 It is of a tan-brown color above, fulvous beneath, with the breast, head, and legs 

 darker, and the wing-covers still darker brown, with four white dots across the base, 

 another behind the middle, and still another near the tip. The thorax is roughly 

 wrinkled, humped, and remotely punctate. It measures about one-third of an inch 

 in length. This is an elegant looking insect, which is much decorated by the 

 silvery white spots of the wing-covers, as also by the small white spots on the sides 

 of the connexivum, flanked by the black ground of the tergum, and the black, trian- 

 gular spots on the margin of the connexivum. It is widely distributed throughout 

 Europe, being found in England, Germany, France, Spain, and Italy upon clear 

 rivers and creeks, from early spring until cold weather in autumn. The unwinged 

 form is stated to be the most common in England, and it is held by the Germans to be 

 a distinct species, which they preserve under the name V. currens. This is quite out 

 of analogy with the other forms of the group, in almost every country where species 

 of this genus have been found. 



O 



A still more beautiful form is the velvety brownish-black V. basalis, which inhabits 

 Brazil. It is a more compact form than the preceding, with a broad head, set more 

 closely against the front of the prothorax, with still longer antenna?, and the bases of 

 the legs and a long spot on the origin of the wing-covers bright yellow. The rostrum 

 is piceous, and extends to the base of the middle coxa?. It measures rather more than 

 a quarter of an inch in length, and is of a deep boat-shaped figure. It lives on the 

 waters in the vicinity of Rio, extends back into the interior of that country, and varies 

 considerably in the size and colors of the spot on the base of the wing-covers. 



A North American form, Mesovelia, with much longer head and somewhat spindle- 

 shaped body, comes here. It constitutes another type of the water creepers which 

 are widely distributed in the United States. Its head is wide and much prolonged 

 before the eyes (as in the genus Limnotreclius) ; there is a distinct interval between 

 them and the front margin of the prothorax, and a constriction across the extreme 

 base. The antenna? are very slender, filiform, longer than the abdomen ; the basal 

 joint is barely a little thicker than the others, of about the 

 same length as the third and fourth, the second joint much 

 shorter than the others, and the antenniferous tubercles are 

 expanded in front so as to give a trumpet-like enlargement 

 to the front of the cranium. From the slightly bent clypeus 

 the slender rostrum extends back to the middle coxa?, the 

 second joint being very long and tapering. The prothorax 

 is contracted into a short, transverse front lobe, but widened 

 at the shoulders, which are tubercle-like and prominent, and 

 the posterior margin is cut almost square off; behind this 

 the scutellum is conspicuous, and has a triangular, callous 

 elevation on the disc and a smaller one behind it. A con- 

 spicuous pair of ocelli occupy the middle of the vertex, 



1 > ' PIG. 324. Mesoveha bisiynata. 



and are placed nearer to each other than to the eyes. The 



wing-covers are of thin texture, narrower than the space between the connexiva, have 

 the corium long, furnished with thick long veins bounding the long and narrow cells, 

 and the membrane with a single, short, straight vein running about half way back from 

 the tip. A remarkably wide, membranous clavus occupies the entire length of the 

 inner side of the corium and curves, while becoming more slender half way along the 



VOL. II. 18 



