612 FAMILY XXII. — MESOVELIID,£. 



4 longer, fusiform. Beak reaching first ventral. Pronotum one-half 

 wider at base than long, its sides rather abruptly constricted about the 

 middle; disk unevenly, sparsely and rather coarsely punctate, humeral 

 angles swollen, obtusely rounded. Basal portion of scutellum with a fine 

 median carina. Elytra, in maeropterous form, reaching tip of abdomen. 

 Length, 1.4 — 1.5 mm. 



Moore Haven, Fla., March 2 ; two specimens swept from low 

 herbage along the side of a ditch. The type and only specimen 

 heretofore known was taken by Mrs. Slosson at Biscayne Bay, 

 Fla. 



Family XXII. MESOVELIID^, Douglas & Scott, 1867, 3. 



The Water Treaders. 



Small, slender, subaquatic species having the head broad, 

 shorter than pronotum, inserted in thorax almost to eyes, 

 ocelli approximate, placed close to its base ; eyes large, promi- 

 nent ; antennae slender, 4-jointed, more than half the length of 

 body ; beak slender, 3-jointed, reaching to or behind middle 

 coxae, joint 2 longer than 1 and 3 united ; pronotum feebly con- 

 stricted in front of middle, the hind lobe convex; scutellum 

 rather large, triangular, its base with an elevated calloused 

 area ; elytra largely membranous, variable in length, some- 

 times entire and surpassing abdomen, more often abbreviated, 

 the corium long, its veins prominent ; legs slender, subequal in 

 length ; tarsi 3-jointed, the basal joint minute, the second much 

 the longest, claws inserted at the end of the third. The fam- 

 ily is a small one, comprising only two genera. One of these 

 is represented by four species in the eastern states. Hunger- 

 ford (1917, 73), writing of the habits of M. mulsanti, our most 

 common species, says : 



"It is at home on the floating vegetation growing in the shallow 

 waters of pools, where the clumps of sedge spread their slender stems 

 upon the water from the bordering bank, where young cat-tails spring 

 up and green alga? carpet the surface of the waters. The writer has 

 found them about old logs projecting from the water, in clumps of smart- 

 weed at the water's edge, as well as on rafts of filamentous alga? and 

 leaves and stems of plants procumbent upon the surface. They are 

 cautious creatures but do on occasion fall upon fairly lively prey. A 

 fly thrown into the aquarium was seen to crawl up the side of the jar 

 bearing an adult female Mesovelia with its beak attached near the caudal 

 end of the fly which when disturbed flew to a near-by support bearing 

 the tenacious little bug. However, the writer has come to believe that, 



