Chironomid deformities as indicators of pollution from a synthetic, coal‐derived oil

SUMMARY. Larval Chironomus decorus (Diptera: Chironomidae), taken from experimental ponds to which a coal liquid had been added, were found to have deformities of the mentum. Aberrations of the medial portion of the mentum were significantly dose-related. Occurrence of such deformities appeared to be a less sensitive measure of pollution by the coal liquid than did previously reported changes in abundance, biomass, number of taxa, and species diversity of benthic insects.