108 SATURDAY LECTURES. 



worms' part in the history of the world, and in a geological 

 sense, is still amazing. 



There are, indeed, very good reasons for believing that all 

 genuine loam is produced solely by worms.. 



" Think naught a trifle, though it small appear; 

 Small sands the mountain, moments make tiie year. 

 And trifles life!"' 



And now, ladies and gentlemen, the limit of time which 

 custom and a due regard for your feelings have established 

 for these lectures has been reached. I had hoped to say 

 something of the scale-insects which are so common and 

 destructive on our fruit trees and other plants, and which 

 give us the lac and tlie cochineal of commerce as they gave 

 the manna to the people of Israel ; to show you how perfect 

 a parallelism may be traced in the history of some of them 

 and that of the oyster: — the active young; the degrada- 

 tional development ; the formation of the shell ; the way it 

 is perforated by parasites, etc., oifer a remarkable instance 

 of the existence of that misleading analogy of function 

 which Prof Gill so abl}' dealt with, in creatures which be- 

 long to different branches of the animal kingdom, and 

 which possess no possible homologies with each other. I 

 had hoped to give you some details of the remarkable 

 hyper-metamorphoses and life-habits of the blister-beetle, 

 of which Ave annualh^ import large quantities under the 

 name of cantharides, when we have a number of indigenous 

 species with as good or better vesicatory properties. But, 

 above all, I wanted to treat of the butterfly, for if the trans- 

 formations of the animals I have already spoken of are re- 

 markable, those of the butterfly from the caterpillar, through 

 the chrysalis, transcend them all, and have always excited 

 the greatest curiosit}^ and wonder; while the feat which the 

 caterpillar in some instances performs in the change to the 

 suspending chr3^salis is really marvelous, and was first prop- 

 erly explained, a little more than two years ago, before the 

 Philosophical Society of this city. I have been able only 

 in the most imperfect manner to treat of the more salient 

 facts in the lives of some half dozen of the numerous ani- 



