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Suborder Zygoptera.
Family Agrionidae.
Austroagrion sp. (Text-fig. 4.)
Damselfly nymphs were commonly found swimming near the surface of the more permanent ground pools about Palmalmal. Feeding experiments were carried out with fully grown nymphs of an unidentified species belonging to the genus Austroagrion (Table 4).
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| Experiment number. | 1 | 2 | 3 | 4 | |
|---|---|---|---|---|---|
| Mosquito species supplied to the predator as food. | Anopheles farauti. | Culex pullus. | Anopheles farauti. | Culex pullus. | Mixture of both species. |
| Developmental stage supplied. | 3rd and 4th instar larvae. | 3rd and 4th instar larvae. | 3rd and 4th instar larvae. | 3rd and 4th instar larvae. | Pupae. |
| Number of larvae or pupae eaten by 2 nymphs of Austroagrian sp. in 5 days. | 101 | 93 | 37 | 48 | 54 |
| Average number of larvae or pupae eaten by a single predator each day. | 10.1 | 9.3 | 3.7 | 4.8 | 5.4 |
In this case the predator ate anopheline and culicine larvae in almost equal numbers, whether they were supplied in pure or mixed culture. Zygopterid nymphs feed at the surface and intermediate
![Thumbnail: [Volume 76, 1946-47 page 464]](/journals/rsnz/images/rsnz_76/thumbnails/rsnz_76_03_0584_0464_ac_02.gif)
Text-fig. 4.—Austroagrion sp., fully-giown nymph.
levels of pools as well as at the bottom, and thus, unlike the nymphs of Anisoptera, encounter larvae of Anopheles as readily as those of Culex. Mosquito pupae are destroyed in some numbers by the nymphs of Austroagrion. The former evidently gain a degree of protection by their habit of progressing by sudden darting movements, and only half as many pupae as larvae were destroyed each day by the agrionid nymphs kept under observation at Jacquinot Bay (Table 4)
As well as attacking the aquatic stages of mosquitoes, the zygopterid nymphs studied ate any other small aquatic animals that they were able to overpower. It is considered that because of their free-swimming habits nymphs of agrionid damselflies are of greater importance as enemies of Culicidae, particularly of larvae of the genus Anopheles, than are those of Anisoptera.