678 THE POPULAR SCIENCE MONTHLY. 



ruinations of both, of these great epochs of mountain-building, so 

 widely separated by the Mesozoic and Tertiary eras, glaciation 

 has been remarkably associated, and indeed the ice accumulation 

 appears to have been caused by the epirogenic and orogenic up- 

 lifts of continental plateaus and mountain ranges. Since the dis- 

 turbances, with glaciation, closing Palaeozoic time, the same com- 

 bination of events has not recurred until the Quaternary era, 

 which is not only exceptional in its accumulation of ice-sheets, 

 but also in its numerous and widely extended movements of ele- 

 vation and subsidence, and in its mountain-building and renewed 

 upheavals of formerly base-leveled mountain belts. The earth's 

 surface is probably now made more varied, beautiful, and grand 

 by the existence of many lofty mountain ranges than has been 

 its average condition during the previous long eras of geologic 

 history. 







MUSICAL INSECTS. 



By HERE E. FEANCHESCHINI. 



IF we would hear the children of the sun, we must shut the door 

 of our prosaic room behind us, and hurry out before the com- 

 ing on of dusk to the pond, into the green field, on the moor, to the 

 edge of the wood where life in the double form of animal and 

 plant unfolds itself without restraint. From up in the air, from 

 plants, flowers, grass, holes in the ground, and the moisture of 

 puddles, come a chirping and rattling, a humming and buzzing, 

 a piping and singing of the host of winged and wingless creeping 

 and hopping insects. Let us guard our steps. Near us a musk- 

 beetle is groping with his long, knotty feelers along the bark of 

 a willow tree. The shrill tone of his chirp strikes upon the ear ; 

 and if we are gifted with musical sense enough we may succeed 

 in hitting the key-note of his register. We need only use our 

 chamber-tone, the treble A, or any other note easy to whistle, in 

 order to determine from it the pitch of the beetle's song. We 

 shall find then that he has the highest-pitched voice in all Nature's 

 concert the third octave of D. From the distance comes a hum- 

 ming which is related to that chirping as the alto to the treble. 

 It is the sound of the vibrating wing of the moss-bee. The buz- 

 zing bass of the bees and wasps is about an octave lower than our 

 chamber-tone A. Within this melodic compass, or the musical 

 space of three octaves and a quarter, lie the voices of all the other 

 crawling six-footed symphonizers. How is all this music pro- 

 duced ? Men and the higher animals have lungs the bellows ; 

 a windpipe; a larynx, the real sounding instrument; and, as 

 mouth-piece, the hollow of the throat and mouth. How can in- 



