Eggshells of Australian Gomphidae: plastron respiration in eggs of stream-dwelling Odonata (Anisoptera)

Eggshells of 10 Austrogomphus, 3 Antipodogomphus and I Hemigomphus species (Gomphinae) were examined using scanning electron microscopy. In 9 Auslrogomphus spp. the outermost eggshell layers were found to carry a field of prominent pillars supporting a gelatinous outer chorion above the general egg surface. Eggs of Antipodogomphus were similar but with pustulate projections in place of pillars. Eggs of 1 Auslrogomphus and I Hemigomphus sp. did not carry such structures. The structures are interpreted as respiratory plastrons.