Tiny Baetis mayflies are perhaps the most commonly encountered and imitated by anglers on all American trout streams due to their great abundance, widespread distribution, and trout-friendly emergence habits.
Beardius on Aug 1, 2008August 1st, 2008, 6:54 am EDT
Several of these pictures show larvae of the midge Epoicocladius (Diptera: Churonomidae: Orthocladiinae) attached to the gills of the nymph. This species is an obligate commensal that feeds on organic material that accumulates on hair tufts at the base of the gills. They are almost always present where burrowing mayflies are present in large numbers. Different species of Epoicocladius are found on Ephemera spp., Hexagenia spp., and Litobrancha sp.
Beardius on Aug 8, 2008August 8th, 2008, 6:46 am EDT
One more thing...keep your eyes open for midges associated with Acroneuria, Paragnetina, Pteronarcys, Nigronia, Corydalus, Epeorus, and Ephemeridae (Litobrancha, Hexagenia, Pentagenia, Ephemera). There are a lot of parasitic and commensal midge species in the genera Nanocladius and Epoicocladius that are associated with these large aquatic insect species. Many of these species are currently undescribed, though I am in the process of describing many of them. A Pitt student recently discovered the habitat and larval stages of another midge genus, Tricochilus, as living inside mussels and feeding on their glochidia (baby mussels). The habitat, larval, pupal, and male stages of this species were unknown for about 100 years until they turned up emerging in a rearing tank for mussels.
The First Fork of the Sinnemahoning, Kettle Creek, Hick's Run, Pine Creek, and other north central PA streams have a lot of these associations for some reason.
Anyway, I'd love to be up north collecting aquatic insects and fishing the evening hatches. Tight lines.