1166 LARVAE AND LARVA-CASES OP AUSTRALIAN APHROPHORID.E, 



This phenomenon does not occur only in this order of insects. 

 It is said that a kind of ant in Brazil absorbs water, and emits 

 it in abundance. ("Nature," 1881.) 



The lime which enters into the composition of the shell is 

 evidently provided from the sap of the tree, and, according to 

 Professor W. A. Dixon, the stems and leaves of gum trees are 

 rich in lime. From a rough assay made by treating the shells 

 with diluted hydrochloric acid, I obtained at least seventy-five 

 per cent as the proportion of carbonate of lime, the insoluble 

 remains being considered as chitinous matter. 



The weight of the ornamented shell, the most common species, 

 is about 4 centigrammes, whilst that of the larger one is 6 

 centigrammes. 



The imago was obtained about the end of September, and 

 was identified by Mr. Macleay as belonging to the genus Ptyehis 

 nearly allied to AphropJwra. 



When it is ready to undergo its last change the larva gets out 

 of the shell in the middle of a frothy mass of water like the 

 cuckoospit (^Aphrophora spumaria, Linn.), and shortly after 

 leaving its skin, appears in the shape of imago. 



About the same time, I received from Mr. John Mitchell of 

 Bowning, some living specimens which were far less advanced 

 than those around Sydney, showing that they were at least one 

 month or two later. 



It is not known when they deposit their eggs, but it is probable 

 that they live for some time in the perfect state, as they are still 

 to be found now (end of November) on the trees. 



These little jumpers don't make great use of their wings and 

 consequently don't go very high on the trees although they run 

 very quickly ; their shells are found from two feet to six or seven 

 feet above the ground. 



Ten months at least ought probably to be reckoned as the time the 

 insect lives in its larval state, at the same time growing its shell. 

 During that period it apparently undergoes numerous changes, as 

 in the three last months of the life of the larva, it passes through 

 at least six distinct stages including the last one. 



By perusing the appended plates we will go rapidly through 

 the details of this study. The scale is marked on the figures. 



