Fig. 1.

Hemolymph flow through the larval and adult dorsal vessels changes during development. a Lateral view of a larva showing the dorsal vessel with ostia. Hemolymph enters the dorsal vessel via a pair of incurrent openings at the posterior heart terminus and exits into the head via an excurrent opening. The larval heart only contracts anterograde. b Lateral view of an adult mosquito during an anterograde heart contraction period. Hemolymph enters the dorsal vessel via paired ostia in abdominal segments 2–7 and exits into the head via an excurrent opening. c Lateral view of an adult mosquito during a retrograde heart contraction period. Hemolymph enters the dorsal vessel via a pair of ostia at the thoraco-abdominal junction and exits the heart via a pair of excurrent openings at the posterior heart terminus. Illustrations are not drawn to scale. The movement of hemolymph is illustrated using dashed arrows