large basiconic sensillum of antennal segment 3 [FBbt_00004175]

Large, olfactory basiconic sensillum of antennal segment 3, measuring around 12 micrometers in length and 2.5 micrometers in width, with a blunt tip (Shanbhag et al., 1999. Directly above the base of the sensillum, the shaft diameter is often somewhat reduced resulting in a club-shaped appearance (Shanbhag et al., 1999. The external sensory structure is perforated by pores, arranged along a complicated pattern of branched lines, that connect to a lymph-filled lumen containing the highly branched dendrites of 2-4 ORNs (Shanbhag et al., 1999. (Shanbhag et al., 1999)