Order Diptera (True flies) 
Courtesy of the Cacapon InstituteHead may be a capsule-like structure with thick hard skin; head may be partially reduced so that it appears to be part of the thorax, or it may be greatly reduced with only the mouthparts visible; no wing pads occur on the thorax; false-legs (pseudo-legs) may extend from various sections of the thorax and abdomen in some families; no segmented legs in the larval forms; thorax and abdomen composed of entirely soft skin, but some families have hardened plates scattered on various body features.  Note: the larval stages do not legs. 



Blephariceridae (Net-wing midge): Head fused with thorax and first abdominal segment; six abdominal segments with deep constrictions between segments; gill tufts present ventrally. Clinger; Scraper; VS-S (L)(F) [Adult]


Ceratopogonidae (Biting midge): Variable characteristics occur in this family, often similar in appearance to Chironomidae; usually a distinct head is visible with small mandibles. Crawler/burrower; Predator; VS-M (H)(F/S) [Adult]


Chironomidae (Non-biting midge): Hardened clearly visible head; long worm-like body; two pairs of prolegs with terminal hooks. Some may be red in color due to a hemoglobin-like compound. Crawler/burrower; Collector/gatherer; VS-L (H)(F/S) [Adult]


Culicidae (Mosquito): Head hardened and separate from the thorax; brush-like hairs near the labrum (upper-lip); thorax is fused and swollen and wider than the abdomen. Swimmer; Collector/gatherer, filterer; VS-M (H)(S) [Adult]


Dixidae (Dixid midge): Head hardened and rounded; prolegs terminate in hooks on abdominal segment one and two; abdomen terminates into two lobes fringed with hairs. Crawler/burrower; Collector/gatherer; VS-M (M)(S/F) [Adult]


Syrphidae (Rat-tailed maggot): Head blunt or reduced and withdrawn into the thorax; 7 prolegs; abdomen terminates into a very long respiratory tube.  Crawler/burrower; Collector/gatherer; VS-M (H)(S) [Adult]



Athericidae (Watersnipe fly): Body long (caterpillar-like); head reduced but may be visible; prolegs on most abdominal segments; abdomen ends in a fringed tail.  The family is often green in color. Clinger/crawler; Predator; S-M (L)(F) [Adult]


Empididae (Dance fly): Body elongated; head reduced or pulled into the thorax; prolegs present on most abdominal segments; prolegs longer on segment eight; abdomen is blunt on the end or terminates in welts. Crawler/burrower; Predator; VS-M (H)(S/F) [Adult]


Muscidae (Muscid fly): Anterior portion of the body tapered, posterior is blunt; head reduced orwithdrawn into thorax; whelps on abdominal segments; abdomen terminates into a pair of respiratory tubes.  Burrower; Predator; S-M (H)(S/F) [Adult] 


Psychodidae (Moth fly): Head hardened, rounded and separate from the thorax; body segments with two to three secondary divisions (annuli) often having hardened plates. Burrower; Collector/gatherer; VS-S (H)(S) [Adult]


Ptychopteridae (Phantom cranefly): Head hardened and rounded; prolegs present on abdominal segments one through three, terminating with claws; abdomen terminates into a long respiratory tube. Crawler/burrower; Collector/gatherer; M (H)(S) [Adult]


Simuliidae (Black fly): Head hardened and rounded bearing a pair of labral fans (mouth brushes); prolegs on lower thorax; lower third of the abdomen is swollen (vase-like) and terminates in a ring of hooks. Clinger; Collector/filterer; VS-M (M)(F) [Adult]


Stratiomyidae (Soldier fly): Body is flattened dorsally with a leathery feel; head is reduced but visible; thorax is broader than the head; spiracles at the end of the abdomen for breathing. Swimmer/burrower; Collector/gatherer; S-L (H)(S) [Adult]


Tabanidae (Horse fly): Body spindle shape both ends tapered; head reduced usually not visible; creeping welts with small hooks present on abdominal segments one through seven; no prolegs. Crawler/burrower; Predator; M-VL (H)(S/F) [Adult]


Tipulidae (Crane fly): Rounded head capsule, often reduced and barely visible; ventral welts on some abdominal segments; abdomen terminates into a disc surrounded by lobes or tentacle-like projections of varying shapes. Crawler/burrower; Shredder/predator; VS-VL (M)(F/S) [Adult]