Hagen.] 150 [December 27, 



Dr. C. S. Minot made some remarks on the phenomena of 

 growth in man, the rate of which he showed by plotting a curve 

 of " first differences." In such a curve extending from six to 

 eighteen years of age, two slack periods of growth, at seven to 

 eleven years, were noted. 



The Curator called attention to a fine cast of the Pterodactyle, 

 Rhamphorhynchus, the original of which from the Solenhofen 

 slates is the property of Prof. O. C. Marsh, by whom the cast was 

 presented to the Society. 



A vote of thanks for the gift was unanimously passed. 



Section of Entomology. December 27, 1882. 



Mr. George Dimmock in the chair. Ten persons present. 

 The following paper was read : 



CONTRIBUTIONS FROM THE NORTHERN TRANSCONTINEN- 

 TAL SURVEY. 



The genus Colias. 



BY DR. H. A. HAGEN. 



American lepidopterologists have worked on the North Ameri- 

 can species of Colias only during the last twenty years. The 

 only exceptions known to me are the short notice on C. philodice 

 in Harris Injur. Ins. and A. Fitch, notice of the species of Colias 

 in New York in his Insects of Algiers, 1853. (Trans. K. Y. 

 Agric. Soc. Yol. 13. — separ. p. 9-11.) This short notice is rather 

 vague in its statements, and has been criticised by Mr. Scudder. 



Mr. S. H. Scudder published an elaborate paper, 1862, describ- 

 ing three northern species ; and later a fourth one. Mr. W. H. 

 Edwards published, 1863, three new species and in the following 

 years seven ; two of them now considered by him as synonyms. 

 Mr. Reakirt described one species. A very elaborate paper by 

 Mr. H. Edwards was published in 1877. In the meantime Mr. 





