The shaft of the papilla has a longitudinal slit near the distal tip, allowing dendrites of the sensillum to sense the external environment. These dendrites proceed in a wavy form through the shaft of the sensillum. The sensillum contains antennal glomeruli, suggesting that it has an olfactory role. Prakash and colleagues suggest that since the location of this sensilla is in the maxillary palp that this is a short-range olfactory detector for the micro-environment. The olfactory sensilla on the antenna and the double-walled sensilla on both palps probably serve as long-range odour sensors. The maxillary and labial palps show sexual dimorphism which suggests involvement in courtship. Females have more sensilla chaetica on both appendages than males whereas, males have more chemosensilla on the maxillary palps and taste sensilla on the labial palps. According to Schall and colleagues the site of sex pheromone production in the female "Supella longipalpa" is located on the fourth and fifth abdominal tergites. Cuticular pores occur on all tergites, but the density is highest on the lateral margins of the fourth and fifth tergites. Each pore is connected via a long duct to modified epidermal cells, suggesting that these structures are involved in pheromone production. The brown-banded cockroach has been the model in many studies about sex pheromones. Cockroaches rely on pheromones for many reproductive behaviours, including bringing the sexes together for mating. Their sex pheromones can be divided into two categories: cuticular compounds that elicit sexual responses after the sexes contact and volatile compounds that act over a distance. The female brown-banded cockroach emits a sex pheromone that attracts males. Charlton and colleagues isolated and identified the pheromone as 5-(2,4-dimethylheptanyl)-3-methyl-2"H"-pyran-2-one which they refer to as supellapyrone. A blend of synthetic compound elicited behavioural and electrophysiological responses comparable to the natural pheromone. This sex pheromone can be synthesized by direct coupling of a brominated pryoned with an alkylzanic reagent. The stereochemistry of the natural pheromone was assigned by a combination of synthesis, chiral gas chromatography, and electrophysiological measurement.