NATURAL SCIENCES OF PHILADELPHIA. 35 



entered a protest. To this distinguished entomologist, they have 

 every appearance of worms. Leaving this form, therefore, as un- 

 satisfactory for our present purpose, another advance in time 

 brings us to the Jurassic period, where more reliable information 

 is awaiting us. In Europe, where the formations characterizing 

 this period are developed on a singularly grand scale, but two forms 

 of extinct Lepidoptera have been discovered to my knowledge, and 

 these are a moth pertaining to the lowest family, the Tineids, of 

 which the clothes-moth is a well-known example, and a Sphinx. 



In an uninhabited region beyond the Rocky Mountains, near 

 the union of the White and Green Rivers, Colorado, exists a de- 

 posit, probably far richer in insect remains than that of (En in gen 

 in Germany. In two localities separated by a scope of country 

 about sixtj r miles wide, called by Prof. William Denton, Chagrin 

 Valley and Fossil Canon, considerable remains have been found. 

 It is peculiarly interesting that these two regions have every indi- 

 cation of being distinct; the ants, the moth, and the thrips, near- 

 ly all the small coleoptera, and the bulk of the diptera, come from 

 Fossil Canon ; while the larva are restricted to Chagrin Valley. 



While no definite conclusion can be arrived at respecting the 

 age of the beds in which these remains are found, there can be 

 little hesitancy in assigning them to the Tertiary epoch. Profes- 

 sor Denton affirms them to be at least as old as the Miocene. As 

 far as our present knowledge extends, the great Tertiary epochs 

 rank pre-eminently above all others in their yield of fossil lepidop- 

 tera. 



In confirmation of my position that butterflies are a higher type 

 of Lepidoptera than moths, the former being the modified descend- 

 ants of the latter, through several lines of development which had, 

 during aeons of cycles, gradually almost entirely lost their cocoon 

 making propensities, Paheontology, the key which has unravelled 

 so many mysteries in biological science, lends its all-potent influ- 

 ence. 



It has been seen that the earliest of moths of which the globe 

 bears any record, belongs to the Tineids, the lowest family of Le- 

 pidoptera. This is what our theory presupposes. As the larvae 

 of these moths generally construct at the present day cocoons of 

 remarkable compactness, analogy would seem to argue a nearly 

 similar habit in their early progenitors of the dark days of the Juras- 

 sic period. If it were possible to bring the cocoons of species so 



