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1. Highly branched gills present on sides and venter of all thoracic segments (Fig 2.1). . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . .. . . . . . . .. . . . . . . . 2

Gills absent, or restricted to cervical coxal area or fingerlike without numerous filaments (Fig. 2.2). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2. Gill tufts present on abdominal sterna 1-2 or 1-3, habitus large, dark, gill-bellied (Fig. 2.3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pteronarcyidae

Gill tufts absent from abdominal sterna 2-3 (Fig. 2.1), habitus patterned, coxal-gilled . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Perlidae

3. Coxae with single, telescoping gills (Fig 2.4), or abdomen with large triangular ventroapical plate; basal and mid tarsal segments subequal in length (Fig 2.5), habitus swept-winged with long abdomen (Fig 2.6) . . . . . . . . . . . . Taeniopterygidae

Coxae gills and ventroapical abdominal plates absent (Fig 2.2); second tarsal segment wedge-shaped and shorter than basal segment (Fig 2.7) . . . . . . . . . . . 4

Etc.....

 

 

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Scientific keys are not everybody's favorite application. It is often stated that "keys are documents written by those who don't need them for those who can't use them." True, they are rather dry, but if you want to learn the genus and species names of specimens you have collected, it is the way to go. Gross morphology will get you to family (see the Family pictures on the lower part of the Home page and Pictorial Key to Families), occasionally to genus, but rarely further. You have to get out your microscope and look at the fine detail.

Scientific keys are dicotomous keys, that is, they have two choices at each step. Either the specimen has the detailed structure, or it doesn't. Look at the key below. Does the specimen have highly branched gills on sides and venter of all thoracic segments? If yes, go to step 2; if no (not highly branched), go to step 3. If you don't know what the term means (say, venter or thoracic), perhaps the figure will help, or go to the "Terms" frame at the top of every page.