Azilia

1. Anatomy of the genera Azilia, Nephila and Cyrtophora (Araneidae)

As shown in three earlier papers (Palmgren 1978 a & b, 1979), all species of the family Tetragnathidae studied by me differ from all species of other araneomorph spider families that I have dissected in the following respects: They have a posterior unpaired dorsal caecum (behind the dorsal apodeme) and lateral caecal branches extending not only to the coxae of the walking legs but also to the chelicers and, with the possible exception of Tetragnalha (Eugnalha) striala, to the pedipalps; these lateral branches protrude between the tergo-coxal muscles as pouches which extend more or less along the margin of the cephalothorax and contain guanine crystals. None of the species of the family Araneidae, including the genus Meta, share these features with the tetragnathids. The conclusion that Mela should not be included in the family Tetragnathidae (cf. Locket et al. 1974) is in accordance with Homann’s views, founded on the anatomy of the eyes.

Professor H.W. Levi pointed out to me that the anatomy of the genera Azilia, Cyrtophora and Nephila would be of interest as an argument in a discussion of their systematic position and the distinction between the subfamilies of Araneidae (incl. “Tetragnathinae”), and he kindly provided me with some specimens (9$) of Azilia affinis (O.P.-Cambr.) and Nephila clavipes (L.) from Florida, and of Cyrtophora moluccensis (Doleschall) and Nephila maculala (Fabr.) from New Guinea (Wau). The preservation of Azilia was excellent. In the other specimens, the brain and the cheliceral and pedipalpal ganglia in particular had suffered maceration, but all essential features of the musculature and the intestinal organs could be clearly distinguished. When necessary, two specimens were compared.