BY F, RATTB, BNG, ARTS AND MANUP., PARIS. 1165 



But these are not true shells like those of molluscs or serpulse. 



At the meeting of June last, our President, Mr. C. S. 

 Wilkinson, exhibited helicoidal shells of insects found on the 

 branches of some gum trees at the Hunter Eiver. They are 

 figured in connection with this paper, but were remains of the 

 last year, and had no insects in them. Mr. Brazier found some at 

 the North Shore years ago, but they do not seem to be common 

 everywhere. However, Mr. Eamsay found an empty specimen 

 at Manly, probably of the same species. 



Similar shells, but of a conical shape, of two or three different 

 species, are rather common around Sydney, especially on white 

 gum {Eucalyptus hcemastoma, var. micrantha) and stringy bark 

 {Euc. capitellata) ; it is those which enabled me, with the help 

 of Mr. Macleay, to find the genus to which, most probably, the 

 three or four mentioned species belong. Those are true shells, 

 much resembling some living and fossil serpulse. 



The shell is fixed on the branch, generally a little or imme- 

 diately above the insertion of a leaf ; and its opening is turned 

 upwards. The position of the larva in it is reversed, its head 

 being placed downwards, except in the helicoidal shell, where 

 the insect lies horizontally for the greater part of its larva life. 

 In both instances it follows that the larva, instead of presenting 

 its head at the entrance of its shell, like a mollusc, presents its 

 hind region. The mouth of the larva is transformed into a 

 suctorial apparatus, with which it pierces the bark of the stem, 

 and sucks the sap. For that purpose the shell is provided with 

 a longitudinal slit. It occasionally moves itself backwards and 

 emits a drop of clear water at the entrance of its shell, which is 

 habitually half or nearly full of water. In warm weather 

 especially, the production of water is increased, and drops are 

 seen falling from the top of the shell. A well-known species of 

 Aphrophora,^.^. ,^oudoti (Benn), of Madagascar, also lives on 

 trees, but does not build a shell. In the state of larva, as well 

 as of imago, it emits a large quantity of clear water. Mr. 

 Goudot says that on a warm day he could obtain in half-an-hour 

 about a bottle-full of water produced by about sixty insects. (I.) 



(1.) Beimet. Proc. Zool. Soc, Lond., 1833, and Proc. Nat. Hist. Soc, 

 Mauritius, 1832. 



