Volume III 
MARCH AND JULY, 1904 
Nos. 2 & 3 
EXPEEIMENTAL AND STATISTICAL STUDIES 
UPON LEPIDOPTEKA. 
I. VARIATION AND ELIMINATION IN PHILOSAMIA CYNTHIA. 
By henry EDWARD CRAMPTON, Ph.D. 
Pag€ 
Prefatory Statement 113 
I. Introduction 114 
II. The Material and its Treatment 115 
III. Pupal Elimination : — A. Males 118 
B. Females . . 120 
IV. Pupal-Imaginal Elimination : — A. Males 122 
P>. Females 124 
V. The Comparative A^'ariability of Males and Females 126 
VI. Discussion and Conclusion 127 
Prefatory Statement. 
The present paper consists of an account of a detailed study, by means of 
statistical methods, of the facts of variation and of the relation between variation 
and selection in the pupae of the Ailanthus silk-worm moth, P. cynthia. The 
observations here recorded were made more than four years ago, and they have 
been continued and extended in subsequent years upon the same and other species 
of Saturnids. Naturally the scope of the later investigations has materially 
widened, and in addition to the fundamental problem mentioned above, the 
existence of sexual selection has been examined, as well as a host of other 
questions which relate to the process of evolution and its factors. Among these 
may be mentioned the comparative variability of the two sexes, the variability of 
individuals at various stages in their life-history, the comparative variability of 
native and introduced species, and the relation between an introduced species and 
the same species in its original habitat. The problem of inheritance in pure 
Biometrilra iii 15 
