A comparative morphological study of the structure and distribution of sensilla on the maxillary
and labial palps in representatives of the family Hydropsychidae was performed. Morphology of
palpal sensilla was studied in 17 species from 12 genera by scanning electron microscopy. Four types
of sensilla were found on the palps of the studied species: long trichoid sensilla, chaetoid sensilla,
campaniform sensilla, and petaloid sensilla; basiconic and pseudoplacoid sensilla were not found on
palps. All studied species lack apical sensory complexes at the tips of both pairs of palps, where only
long chaetoid sensilla are present. Petaloid sensilla form sensory fi elds on the 4th (in Arctopsychinae)
or on the 3rd and 4th segments (in Diplectroninae, Hydropsychinae, Macronematinae) of the maxillary
palps. These sensilla are never present on the labial palps. Sensory fi elds include from 5–10 sensilla in
Hydropsychinae to 40 in Arctopsychinae.