Hilgendorf. — Insect-life at Cass Mountain Biological Station. 141 



Of the Diptera by far the commonest is the gnat Chironomus, about 

 7 mm. long, which frequently occurs in such numbers that its swarms 

 appear at a distance like columns of smoke. Various crane-flies are also 

 common, the most noticeable being Tipula novarae, 25 mm. in length, 

 and with a wing-span of 45 mm. T. obscuripennis and an unnamed species 

 also occur. One particular moth, Xanthorhoe clarata, a handsome species 

 with wavy lines of brown and yellow on the forewings, which are about 

 40 mm. across, has been captured only on the swamp-land, but its real 

 home is probably in the adjacent shrubs. 



v 



3. The River-bed. 



In the waters of the rapidly running streams are to be found the larvae 

 of the sand-fly {Simulium australense) hanging to or crawling on the upper 

 surface of the submerged stones, and there also occur underneath the stones 

 larvae of the several Neuroptera to be mentioned immediately. These 

 together with the sand-flies hover over the stony or shrubby banks of the 

 river, or drift on to the tussock. The commonest species is Coloburiscus 

 humeralis, with a wing-span of 30 mm., and three tails, the two outer of 

 which are considerably longer than the body. Pseudoeconesus mimus occurs 

 near streams in the forest. Pseudonema obsoleta, whose larva inhabits bored- 

 out twigs in the forest-streams, is strongly attracted to light, and some- 

 times occurs in hundreds on the windows of the station. Its wing-expanse 

 is about 35 mm. to 40 mm., and its antennae reach a length of 45 mm., being 

 about three times as long as its body. Hydriobiosis umbripennis, whose 

 larva is remarkable in that it does not live in any kind of case, occurs 

 commonly. It has a wing-expanse of 25 mm., the front wings being sooty 

 brown and the back ones transparent. Besides these there are one or 

 perhaps two species of Epheniei idae that have not been so far identified, 

 and the larva, but not the adult, of some species of Oniscigaster has been 

 captured. 



The river-bed is rich in other insects besides the Neuroptera. The moth 

 Crambus xanthogrammus is very plentiful, flitting from stone to stone when 

 disturbed. Its wings have a span of 25 mm., and the forewings are marked 

 with broad wavy lines of black and white. I have not seen this moth 

 elsewhere than on the river-bed, and regard it as very characteristic of this 

 association. Several striking flies also occur, chiefly Anabarhynchus inno- 

 tatus, with its bluish-grey body 14 mm. in length ; Calcager apertum, of 

 almost equal size ; and the small Trypeta mentioned before as occurring 

 on the tussock. At least one large but unidentified bee occurs on the 

 river-bed, but nowhere else, so that, on the whole, this is a very distinct 

 association, and a very numerous one considering the limited number of 

 apparent food plants. 



4. The Shrub-land. 



The insects of this association are much fewer in number than would 

 have been expected — unless, indeed, species more easily captured else- 

 where in reality belong to the shrub. Among the beetles the green manuka- 

 beetle (Pyronota festiva) is sometimes common, but remains unseen unless 

 it is found away from its natural background. The rarer P. sobrina, with 

 its bronze elytra, may also be found. Clay banks in the open spaces swarm 

 with the active Cicindela tabercidata ; and the yellow-spotted black lady- 

 bird, Vedalia cardinalis, occurs rarely. The same clay open spaces are 

 frequented by great numbers of the hymenopterous Dasycolletes purpureus, 



