72 Cincinnati Society of Natural History. 



I have been somewhat at a loss for a subject for this address. The 

 history- and condition of our Society are so fully given in the pages of 

 its Journal, that any further reference thereto would be de trop; and 

 my limited time and limited facilities for keeping abreast of the cur- 

 rent of scientific discoveries and thought, preclude me from entering 

 upon even a synopsis of the history of science, or of scientific publica- 

 tions during the past year. Indeed, the progress of scientific research, 

 and the subdivision of labor among scientists, in our time, are so great 

 that few of those who are notable to devote their whole time to science, 

 are able to keep themselves fully informed of all that is being done 

 even in any one special branch. 



An address upon an occasion like this, to a mixed audience of scien- 

 tists, and of people who make no pretensions to science, ought to be 

 of a general and semi-popular character, so as to afl^ord something of 

 interest to all. But the question in the present instance is not what 

 such an address ought to be, but what under the circumstances it 

 7nust be. And rather than venture upon subjects which a scientist 

 familiar with them might make interesting to you, 1 have deemed it 

 best to keep within the narrow limits of a specialt}' to which I have 

 given some attention, and of which have some knowledge. I have ac- 

 cordingly made choice of the subject of The Metamorphoses of In- 

 sects AS Illustrated in the Tineid genus Lithocolletis of Zeller. 



Much that I may have to say will no doubt be familiar to some of 

 you, though in such an audience as this, there are no doubt others to 

 whom the whole subject is terra incognita. 



The word metamorphoses includes all those changes which an or- 

 ganism undergoes in form and structure in the course of its develop- 

 ment from the egg to maturity. In this sense all animals undergo 

 metamorphoses. But in many animals these changes take place so 

 gradually, that there is no sudden change of form, nor an}' process of 

 ecdysis or moulting of the entire dermal integument. But it has a 

 more restricted meaning, at least in common parlance, such as is given 

 to it when people ordinarily talk of the metamorphoses of an Insect or 

 Crustacean, meaning only those more marked changes of form and 

 structure, which appear to be somewhat sudden, and are accompanied 

 by ecd3^sis or shedding of the skin, as when the caterpillar changes to 

 the chrysalis, and the latter to the butterfly, or when a larva passes from 

 one stage to another of larval life. These changes are observed to be 

 not only apparently sudden, and accompanied by a moult of the in- 

 tegument, but they are also periodical, and have a definite relation to 

 the amount of food consumed in each stage, and to the temperature of 



