but also on areas that are in need of exploration. The bibliography has been further revised 

 with the addition of an index to plant genera and common names and the inclusion of selected 

 additional titles from other parts of the world. 



In our scrutiny of the literature, we were constantly confronted with inconsistencies in the 

 methods of reporting host data and uncertainties in reporting the degree of association of the 

 insect with its host plant. We feel that the ideal report should state as fully as possible the 

 relationships of each insect species in all of its stages with each stage of the plant species. It 

 should also recognize that insect associations range from that of simply a resting site to one in 

 which the insect is an obligatory associate of a single plant species. Many so-called host records 

 signify only that the insect was collected on the plant, and may or may not indicate an actual 

 breeding association. However, indefinite records of this nature should not be hastily discarded 

 until the status of the association can be ascertained, because such records may offer the only 

 clues to the true relationship between the organisms. 



We found no reports which possessed all of the ideal characteristics, although some ap- 

 proached closely (Balduf, 1959 (p. 18); Judd, 1961 (p. 7). Many reports gave only a list of the 

 insects that had been collected on the plant and omitted any explanation of the true insect-plant 

 relationship. Some gave the life histories of a few insects with a list of other insects taken on 

 the plant. 



An excellent example of a desired type of study is the above-mentioned report by Judd, in 

 which he correlates the occurrence of insects during the growth of skunk cabbage (Symplocarpus 

 foetidus). His paper demonstrates that knowledge of the mechanisms by which insects are 

 attracted to plants, or are held there, is an essential and intimate component of one's under- 

 standing of plant-insect relationships. 



The importance of accurate identification of plant species or smaller units is obvious when 

 it is recognized that generalizations concerning insect-host relationships should be based on 

 precise identification. Generic identifications of plants often are insufficient. Likewise, the 

 entomological investigator should work with the smallest taxonomic unit possible. 



Associations, if they are to have validity in the future, may require that documented 

 inflorescence-bearing plant samples with associated insects be permanently preserved for 

 future reference, should taxonomic refinements or misidentifications suggest restudy. 



Several basic botanical references for the United States and Canada which we found useful 

 are: 



American Joint Committee on Horticultural Nomenclature. 



1942. Standardized plant names. ED. 2, prepared by Kelsey, H. P., and W. A. Dayton, 

 editors. 675 pp. J. Horace McFarland Co., Harrisburg, Pa. 

 Anderson, Kling L. 



1961. Common names of a selected list of plants. Kans. Agr. Expt. Sta. Tech. Bui. 117, 

 59 pp. 

 Fernald, M. L. 



1950. Gray's manual of botany. Ed. 8. 1632 pp. Amer. Book Co., New York [etc.] 

 Gleason, H. A. 



1952. The new Britton and Brown illustrated flora of the Northeastern United States 

 and adjacent Canada. 3 v. New York Hot. Gardens. 

 Hitchcock, A. S. 



1951. Manual of grasses of the United States. Ed. 2, rev. by Agnes Chase. U.S. Dept. 

 Agr. Misc. Pub. 200, 1051 pp. 



Hitchcock, C. L., Arthur Cronquist, Marion Ownbey, and J. W. Thompson. 



1955. Vascular plants of the Pacific Northwest. Wash. [State] Univ. Pubs. Biol., v. 17, 

 pts. 3-5. Univ. Wash. Press, Seattle. 

 Kearney, T. H., and R. H. Peebles. 



1942. Flowering plants and ferns of Arizona. U.S. Dept. Agr. Misc. Pub. 423, 1069 pp. 

 Munz, Philip, and D. D. Keck. 



1959. A California flora. Rancho Santa Ana Botanic Garden. 1681 pp. Univ. Calif. 

 Press, Berkeley. 

 Rydberg, P. A. 



1954. Flora of the Rocky Mountains. . . Ed. 2, rev. 1144 pp. The Author, New York. 



