respiration pupal respiration IDOMAL:0002150 IDOMAL:0002150 Mosquito pupae are the only insects that have only the anterior thoracic and the anterior abdominal spiracles functional. Most of the outer surface of the respiratory trumpet is hydrophilic, but the spiracular opening is surrounded by a ring of hydrophobic cuticle against which water forms a contact angle. The 1st abdominal spiracles open into the ventral air space, which is enclosed by the pupal mouthparts, wings and legs and which functions in pupal buoyancy. idomal_namespace