ON SOME OF THE FOSSIL TETTIGID^E. 167 



Masses of insect remains, such as these, might have 

 been swept by a swirling stream into some quiet pool, 

 where an abundance of fine mud in suspension might 

 have covered them, excluded the air, and prevented 

 decomposition. We may reasonably suppose that 

 springs of water in the vicinity of volcanoes might be 

 charged with sulphurous acid gas, and oxidation for 

 a time would thus be delayed until sufficient material 

 had accumulated to form strata of appreciable thickness. 

 Sulphurous acid gas is known to act antiseptically by 

 killing most kinds of bacilli. 



Hemiptera are represented to have lived even in the 

 Carboniferous times of America and Great Britain. If 

 this be so, the family must have been contempora- 

 neous with the gigantic Dicteoptera (cockroaches) and 

 Coleoptera (Buprestidae) which crawled amongst the 

 Equisetums and the tree-ferns of that early period. 



The Triassic rocks appear to have very few Hemip- 

 terous remains preserved in them ; but Mr. S. Scudder 

 has examined some fragments of wings taken from 

 rocks below the Rh^tic or Liassic in Colorado, and 

 some elytra which are referred to the Cercopidse. 

 Specimens, moreover, have been referred to Cimex and 

 Cicada in the Rhaetic formations at Schonen in Sweden. 



Some discussion has arisen as to the orderof insects to 

 which Paloiontiiia ooUtica, found in the Stonesfield slate, 

 should be assigned. Mr. A. G. Butler, the discoverer, 

 referred it to the Lepidoptera ; but Mr. Scudder con- 

 siders, and I think with good reason, that it shows a 

 nearer affinity to the Cicadse. I have drawn on Plate F, 

 fig. 1, the elytron of this fine insect, which must have 

 equalled in size any of our modern Cicadae. 



This discovery places the family Hemiptera-Homop- 

 tera far back in geological times. 



Mr. R. Etheridge, Jr., in his memoir on the ' Mesozoic 

 and Tertiary Insects of New South Wales,' has also de- 

 scribed a fossil Cicada, under the name Cicada Lowei.* 



* Mem. Geol, Survey, N. S. Wales. Palseontology, No. 72, with 

 plates. Sidney, 1890. 



