BIBLIOGRAPHY. 



1. Allen, j. A. 



The influence of physical conditions in the genesis of species. The Radical 

 Review, pp. 107-140. 



2. Bateson, W. 



Materials for the study of variation, treated with especial regard to discon- 

 tinuity in the origin of species. London and New York, pp. xvi + 598. 



3. COCKERELL, T. D. A. 



The fauna of the mid-Alpine region of Custer County, Colorado. Trans. 

 Am. Ent Soc. 



4. Cresson, E. T. 



18S7. Synopsis of the Hymenoptera of .\merica north of Mexico. Trans. 

 Am. Ent. Soc. Suppl. vol., 1887, Philadelphia, pp. 350. 



5. Cressox, E. T. 



1872-73. Hymenoptera texana. Trans. Amer. Ent. Soc, iv, i872-'73, 

 pp. 152-292. 



6. Darwin, Charles. 



1859. The origin of species by means of natural selection. London and 

 New York. 



7. EiMKR, G H. T. 



Die Artbildung und Verwandtschaft bei den Schmetterlmgen. Jena, pp. 

 12-243 ; 4 Taf. 



8. Fox, Wm. J. 



1899. Contributions to a knowledge of the Hymenoptera of Brazil, III 

 (Vespidae). Proc. Ac. Nat. Sci., Phil., 1899. 



9. Gray, A., and Hooker, J. D. 



1881. The vegetation of the Rocky Mountain region and a comparison 

 with that of other parts of the world. Bulletin of the United States Geo- 

 logical and Geographical Survey of the Territories, vol. vi. No. i, 1880. 



10. GULICK, J. T. . . 



1893. Divergent evolution, through cumulative segregation. Journ. Linnean 

 Soc, 1888, vol. XX, pp. 189-274. Rep. in Smithsonian Report for 1891. 



11. Hagen, H. a. 1 j o • 



1882. On the color and pattern of insects. Proc. Am. Acad. Arts and bci., 

 pp 234-267. 



12. Henslow, George. 



1888. The origin of floral structures through insect and other agencies. 

 Internat. Sci. Series, vol. lxiii. New York, pp. xi -f 349. 



13. Hopkins, K. G. ^ -, r 



1896. The pigment of the Piendae : A contribution to the study of excre- 

 tory substances which function in ornament. Philos. Trans. Roy. Soc. 

 London, vol. 186, pp. 661-682. 



1893 Evolution of the colors of North American land birds. Occas. 

 Papers of Cal. Acad. Sci., vol. 3. 



15. Lewis, H. W. -, ^ •, ^ . ^ . 



1897. The Vespinae of the United States and Canada. Trans. Am. Ent. 

 Soc, XXIV, pp. 169-192. 



16. Mayer, A. G. ...,_. 



1866. The development of the wing scales and their pigment in butterflies 

 and moths. Bull. Mus. Comp. Z06I. Harv. Coll., vol. xxix, pp. 209-236. 



(87) 



