Definition: arthropod sensory structures consisting of special sensilla called the scolopidia, which are mechano-transducers and respond mainly to stretch or flexion. In insects, they consist of bundles of internal sensilla, each of which has a cap cell, an enveloping cell and one or more sense cells.
Definition: A compound eye with no separation between the crystalline-cone layer and the retinula, each rhabdom receiving light only from its own corneal lens.
