4626 Entomological Society. 



the influence and economy in situ of such an assemblage it is not easy 

 to speculate ; suffice it therefore to remark that the enormous numbers 

 in which they exist, when compared with the limits within which they 

 are confined, would seem to point to some especial end which they 

 may be presumed to fulfil amongst the insect population of those re- 

 mote upland districts. Meanwhile it is far from improbable that, like 

 many of the Nitidulidae and the xylophagous groups, they may assist 

 materially in the decomposition of the superfluous masses of loose 

 rolling timber with which the damp ravines and dense mountain slopes 

 of Madeira everywhere abound. To such localities it is that they are 

 exclusively assigned, occurring in the greatest profusion in those spots 

 which are the least accessible, and where consequently the primaeval 

 timber is, except by the hand of man, most untouched. In their 

 habits the Tarphii are strictly nocturnal, adhering to the under sides 

 of moist decaying logs of wood, felled timber, and even stones during 

 the day, and being only active apparently by night. From 2000 to 

 5000 feet above the sea may be said to include their range ; neverthe- 

 less they are more peculiarly abundant from 3000 to 4000 feet, and it 

 is perhaps towards the upper edge of these bounds that they find their 

 maximum. * * Considering the inaccessible nature of their favorite 

 localities it is far from improbable that many species will remain for 

 ever undiscovered, a possibility which is not lessened by the fact either 

 of the remarkable manner in which they are able to counterfeit death, 

 and so elude observation, or of the near resemblance of the dull rusty 

 colouring of their uneven and inanimate-looking surfaces to the stones, 

 lichen and portions of rolling wood to which in the day time they re- 

 main firmly fixed." We are all aware of the creaking sound emitted 

 by Aromia moschata and many other longicorns ; we all know that this 

 noise is accompanied by a movement of the great central articulation 

 of the body, that of the prothorax with the mesothorax, and we all at- 

 tribute the creaking to the friction of some part of the prothorax on 

 some part of the mesothorax. Mr. Wollaston is not content with this 

 theory, although self-evident, but has been at great pains to discover 

 the exact truth, and has detected and described the mechanical appa- 

 ratus by which the sound is produced, and tested his conclusions by 

 producing similar sounds at pleasure and with Nature's own instru- 

 ments : he finds in the genera Deucalion, Parmena and Dorcadion, a 

 narrow space in the shape of an isosceles triangle (the apex being 

 turned towards the scutellum), which occupies nearly the entire length 

 of the mesonotum, and which, from its brightness, appears at first sight 

 perfectly smooth, but when viewed under a microscope is seen to be 



