Some Easily Confused Macroinvertebrates
Photos taken from McCafferty's Aquatic Entomology
More complete descriptions available on line:
http://www.iso.gmu.edu/~avia/page1.htm

 

 

 Mayfly

 Stonefly
        Three Tails            Two Tails
        Gills on sides of abdomen            No gills on abdomen
        One set of wing pads            Two sets of wing pads
        Legs stretched to the sides            Legs stretched to the sides
        Six legs            Six legs

 

 Caddisfly
                     Two brushy tails, with hooks (usually)
                     If have gills, gills are underneath abdomen
                     No wing pads
                     Legs held in front of body
                     Six legs
Other notes: Lots of variation: some will be in cases, some with be fat and fleshy, some thin. Most common one is pictured above. It is a free-living caddisfly (no case) and will have three hardened plates.

 

 

 Midge Fly

 Black Fly
Black Fly          No tails - have a suction pad instead
No gills          No gills
No wing pads          No wing pads
Proleg held under body          Proleg held under body
One proleg          One proleg
Long, thin body - does not thicken at end          Body thickens into a rounded abdomen
Head clearly visible - no projections from head          Head has mouth brush
Tend to "convulse" when moving          Tend to attach to surface
   

 

 Crane Fly
                               No tails - fingerlike projections instead
                               No gills
                               No wing pads
                               No legs
                               Thick, catterpillar-like body
                               Body often semi-transparent

 For drawing, see #16 on your bug ID sheet

 Beetle Larvae
                     No tails - but gills often pulse in and out
                     Gills are sometimes found on end
                     No wing pads
                     Legs held in front of body usually
                     Six legs
                     Notes: Body is hardened and armored looking. Lots of variation