20-28 mm (2)(3); 24 mm (4); (reference missing for earlier size range given here as 20-33 mm)
Identification
Adult black, including wings, or nearly black, brown-purple; larva whitish, banded with black, up to 50 mm(2)
Range
se. Canada to FL-TX & n. Mexico(4); primarily eastern, although recorded throughout US (Long 2001)
Habitat
Very wide range of habitats; generally near aquatic environments (Long 2001). Larvae live "along the margins of ponds and ditches"(5).
Life Cycle
Larvae require two years to complete life cycle(6)(2); adult males short-lived; females survive through fall(6). Eggs laid on vegetation overhanging permanent water(3)
Remarks
prone to attack cattle and other livestock(2), rarely bites people. Can transmit diseases such as surra and anthrax and be a serious problem for livestock (Long 2001)