Morphological Deformities in Larvae of Procladius Skuse (Diptera: Chironomidae) and Their Biomonitoring Potential

Morphological deformities in Procladius larvae from sites in eastern and western Canada are described and compared. A framework for categorizing deformities in individual head capsule structures is presented to serve as a basis for indexing the severity of individual deformities and, eventually, to provide a more accurate measure of community response to contaminants. Comparison of morphological responses between Chironomus and Procladius suggest that Procladius is the more tolerant of environmental contaminants. It is proposed to use these differences in response to extend the range over which contaminant concentrations can be monitored.