8 THE CAUSES WHICH PROPAGATE 



whose effeminate habits are coeval with the wheel and loom, 

 and who formerly found the fleecy backs of the mountain 

 flocks suffice their wants. But how, again, could Clothes 

 Moths have existed before sheep were ? Was there ever such 

 an ag-e ? 



These and such like speculations must from time to time 

 spontaneously arise in the mind of the collector, especially if he 

 happen to have carried a geological hammer and bottle of acid 

 into the wilds to unclose the record of the rocks; and, as so 

 happens, a life aspect is all the latter science wants when deal- 

 ing with its successive births of extinct beings ; for these must 

 have lived and been subject to existing law — they are found 

 entombed in various stages of growth, entombed as male and 

 female, and besides ai-e in no wise incomplete, deformed, or of 

 monstrous growth, as certain poets have fabled. And this is 

 true of the oldest insects discovered in our coal mines, as of the 

 earliest king crabs. 



In 1871 the sounds produced by insects and their import 

 began to occupy attention, and about the same time the 

 " Descent of Man " was in the zenith of its reputation. My 

 notice nevertheless was independently drawn to this subject 

 from a query in '^The Annual^'' by Dr. Knaggs, as to whether 

 the Silver Lines Moth was capable of uttering a cry. I soon 

 after picked up coj)ies of Kirby and Spence and Rennie^'s 

 " Miscellanies " at an old bookstall, and finding myself within 

 a short walk of the libraries and natural history collections of 

 the metropolis, was not only enabled to dissect the insects I 

 found in the fields and eligible building plots around Maida 

 Vale, but likewise to systematically read up the investigations 

 of others in English and foreign works. The organs of hearing 

 in moths I stumbled on by the merest chance during the course 

 of the summer of 1871, and for a long time I fancied these 

 structures had some connection with the sound made by insects 

 during flight ; under which impi'ession some amicable notes 

 passed between myself. Dr. Knaggs, and Mr. M'Laehlan, 

 which eventually led to certain communications finding pub- 

 licity in the Entomologists' Monthly Magazine, for which I 

 have to tender acknowledgments to the editors, especially to 

 Mr. Doug-las. 



