HUNGERFORD: AQUATIC HEMIPTERA. 99 



Summary. In addition to the notes made by Martin and Bueno, the 

 writer has been able to determine that while they may feed upon insects 

 trapped upon the water, their main supply comes from emerging midges, 

 Ostracods and mosquito wrigglers. They respond much more quickly to 

 the activity beneath the surface than to that above. They may lay 175 

 or more eggs and as many as eleven in one day. The average time for 

 the incubation of the egg is 7 days, with a range from 4 to 22 days. 

 Each nymphal instar requires on the average 2 days. Sometimes three 

 or four, and in a couple of cases, only one day. The complete cycle from 

 egg to egg, under the most favorable conditions, lasting 15 days. 



Family MESOVELIID^ D. & S. 1867. 

 A. Taxonomy of Mesoveliid^. 



Description. These are small, rather slender, green or yellowish- 

 green bugs. The adults may be winged or apterous. (In the latter case 

 the adults are distinguished by a broad connexvium.) Antennae four- 

 segmented, filiform. Ocelli are present in the winged adults but "ob- 

 solescent" in the wingless forms. Rostrum three-segmented, tarsi three- 

 segmented. One genus, embracing one North American species. 



Historical review. Since these bugs were first made known to science 

 in 1852 by Mulsant and Rey, through the descriptions of Mesovelia 

 furcata, there have been added a few other species. Among them one de- 

 scribed by F. B. White from the Hemiptera collected in the Amazons by 

 Prof. J. W. Trail and named Mesovelia midsanti. Uhler gave to our 

 American species the name of M. bisignata and speaks of it at some 

 length in Kingsley's Natural History. 



Van Duzee regards this M. bisignata as a synonym of M. mulsanti 

 White. 



The phylogenetic relationship of this little group has been somewhat 

 of a puzzle. Mulsant and Rey assigned the genus to the family Hebridae. 

 Dohrn, 1857, in his Catalogus Hemipterorum places the Hebrids and 

 Mesoveliids together under what he calls "Ductirostri" between the 

 Mirids and Tingidids. Baerensprung, 1860, in the "Catalogus Hemip- 

 terorum Europae" includes the Gerrids, Veliids, Hebrids and Hydro- 

 metrids in the family Hydrometridse. Douglass and Scott, 1867, were 

 the first to disengage them from the others. These writers set them 

 apart with tribal rank. On the whole, writers assigned them to kinship 

 with the various waterstriders and treaders until Reuter, 1912, removed 

 them to a position with the Hebridae between the Reduviidae and Nabidae, 



General Habits. These insects are to be found upon and about the 

 blankets of algae, duck meat, etc., floating upon quiet pools. They take to 

 the open water when disturbed, where they are able to propel themselves 

 with a fair degree of success, running upon the water rather than row- 

 ing, as do the Gerrids. 



Genus MESOVELIA M. & R. 1852. 

 Besides the characterization given under the family description, and 

 in the absence of the original generic description,, there is little that the 

 writer dares to hazzard concerning the generic description. The pro- 



