82 
AUTHORS CONSULTED. 
Comstock. J. H. Bulletins Cornell Univ. Exp. Station. Introduction to Ento- 
mology. 
Edwards, H. Bibliog Catalog, of Described Transformations of North American 
Lepidoptera. Bulletin of the U. S. Xat. Mus. No. 35. 
Ferxald. C. H. Butterflies of Maine. 
Fletcher, James. Reports of Entomologist Central Experimental Farm. Canada. 
Forbes, S. A. Reports of State Entomologist, Illinois. 
French, G. H. Butterflies of the Eastern United States. 
Gillette. Bulletins Iowa Experiment Station (especially No. 12). 
Harris, T. W. Insects Injurious to Vegetation. 
Llstxer, J. A. Reports of State Entomologist of Xctv York. 
Osborn, Herbert. Ann. Rept. U. S. Dep. Ag. 1887. Bulletins 22 and 23, Div. Ent. 
U. S. Dep. Ag. Bulletins Iowa Exp. Station. 
Perkins, G. H. Annual Repts. Vermont Experiment Station. 
Riley, C. V. Reports State Entomologist of Missouri. Reports Entomologist U. S. 
Dept. Agriculture. Bulletins Div. Ent. U. S. Dept. Ag. (especially No. 25). 
Slixgerlastd. M. V. Bulletins Cornell Univ. Experiment Station. 
Webster. F. M. Bulletins Ohio Experiment Station. 
In discussing this paper Mr. Hopkins stated that he had not studied 
the insects mentioned by Mr. Osborn as causing the failure of grass 
fields, but that he had observed that if land on which grass is "run 
out " is plowed in July and sown to grass seed by the first week in 
August a good crop of hay would be obtained the next July, and that 
the crop gradually diminishes from year to year until this treatment is 
repeated. 
The following paper was then read : 
NOTES ON METHODS OF STUDYING LIFE HISTORIES OF INJURIOUS 
INSECTS. 
By L. O. Howard, Washington, D. C. 
In the pamphlet entitled "Directions for Collecting and Preserving 
Insects," published by Dr. Eiley as Part F, Bulletin 39, of the National 
Museum, the chapter on " The Bearing of Insects," occupying pages 
112 to 120, comprises in general and in condensed form the results of 
the experience of the office with which I am connected. Excellent 
remarks will be found under the heads of " General Directions," " The 
Breeding Cage or Vivarium," and "Detailed Instructions for Bearing," 
together with some consideration of the root cage, special apparatus, 
and the insectary. Under the head of " Detailed Instructions for 
Bearing," the greatest attention is paid to the best methods of study- 
ing the life histories of Lepidoptera, but the subjects of out-door obser- 
vations of insects possessing alternate food plants, such as the Aphi- 
