Methods of Study

In 1994 I began to reexamine the Neotropical fauna as part of our study of the caddisflies of Costa Rica (Holzenthal 1995). I have since expanded that study to include all of the Neotropical species. My examination of the Costa Rican species in the gemma group indicated that wing color patterns, body and eye size, and male genitalia were all useful in distinguishing among species. Ross and others pointed out that male genitalia were insufficient to differentiate species. I found that by carefully preparing and examining male genitalia using high quality optical equipment (Olympus BH-2 compound microscope and Olympus SZH and SZX stereomicroscopes), and by examining large series of specimens where available, I was able to find consistent, if sometimes slight, differences in a number of genitalic features. These always correlated with differences in color pattern, eye size, or body size resulting in distinct, diagnosable species.