Marpissoida: Dendryphantinae
Two of North America's three Zygoballus species occur in Massachusetts. Z. sexpunctatus does not occur in the state but I have included an "Identification" section on the species page for comparison. George and Elizabeth Peckham wrote the original descriptions of both Massachusetts' species (Z. rufipes and Z. nervosus). These primarily eastern species are fairly widespread from Canada southwards. Hentz described the third species (Z. sexpunctatus) that to date has been found only in South Carolina, Florida, and Texas. A fourth species originally described by the Peckhams as Z. bettini was "lumped" with Z. rufipes by Edwards and is now considered a northern varient. Ryan Kaldari is presently working on this genus and his efforts in conjunction with the original descriptions have helped to clarify the specific characteristics of North American Zygoballus spiders.
Peckhams 1885, 1888, 1909; Emerton, 1891; Edwards, 1980; Richman, Cutler and Hill 2012; Hill and Edwards, 2013