308 



SCIENCE, 



[N. S. Vol. XXIV. No. 610. 



yet incapable of exact control; errors whicli 

 are small but yet significant in the light of 

 the magnitude of sugar transactions. 



Geo. W. Eolfe. 

 ToA Baja, Pobto Rico. 



SPECIAL ARTICLES. 

 A BURIED TREASURE OF ECONOMIC ORNITHOLOGY, 



In 1865 there was published in New York 

 a work on entomology by Dr. Isaac P. 

 Trimble. Though dealing primarily with in- 

 sects, the book contains the most original and 

 accurate observations then made in economic 

 ornithology in America. Concealed under its 

 caption, *A Treatise on the Insect Enemies 

 of Fruit and Fruit Trees,'^ is a mine of in- 

 formation concerning the relations of birds to 

 some of the worst pests horticulture has to 

 endure. 



The attention to minutiae and the scientific 

 accuracy with which the data were gathered 

 are remarkable for the time, and the line of 

 investigation, undeveloped as it was. While 

 Samuels, Michener, Flagg, Bryant, Jenks and 

 others were working in the field of economic 

 ornithology at that or a little earlier period, 

 the work of few, if any of them, is marked 

 by the wealth of definite information that 

 characterizes the labors of Trimble.* His 

 specific identifications of substances found in 

 the stomachs and his technique of determina- 

 tion savor strongly of present methods, and 

 at once distinguish his work from most of the 

 contemporaneous articles on the subject, be- 

 ing, as often they were, mere compilations of 

 Audubonian and Wilsonian phrases. 



Dr. Trimble went to the birds themselves 

 for his information. He says: 



^ William Wood and Co., New York, 1865, pp. 

 139, pis. XI. This title is not to be found in Coues's 

 bibliography nor in any list of publications con- 

 cerning economic ornithology. By entomologists, 

 however, the publication is frequently cited some- 

 times even for its ornithological matter, and its 

 author is deemed entitled ' to a prominent place 

 with the early economic entomologists of the 

 country.' 



- The latter says, however, of the work of Flagg, 

 * Of the many contributions to the history of 

 birds, I have met with none so interesting as this ' 

 (p. 113). 



I have killed a very large number of birds and 

 examined the contents of their stomachs, especially 

 of those frequenting orchards. Most of these 

 examinations have been made with a magnifying 

 glass, and many with the microscope. Some species 

 I have shot at short intervals during the season, 

 to know how far their food varied at different 

 times; and I have thus ascertained that the con- 

 tents of the stomach at any one time are not an 

 infallible criterion by which we can determine the 

 usual food of that bird. On the fifth of May, 

 1864, I shot seven different birds; they had all 

 been feeding freely on small beetles, and some of 

 them on nothing else. There was a great flight 

 of these small beetles that day; the atmosphere 

 was teeming with them. A few days after the air 

 was filled with ephemera flies, and the same 

 species of birds were then feeding upon these (p. 

 113). 



Here he recognizes the law that birds as a 

 rule feed upon substances most abundant 

 about them, a fact with which we are con- 

 stantly brought face to face in the more ex- 

 tensive investigations of the present time. 

 Continuing the comparison, as we identify 

 some beetles by the scutellum or chrysalides 

 by the cremaster, he also had his little niceties 

 of method, of one of which the following is 

 an interesting description: 



The eyes of most insects are wonderfully formed. 

 They may be said to be compound eyes, each made 

 up of many hexagonal lenses. If a comb of 

 the hive bee, containing one or two hundred 

 cells, could be photographed down to the size of 

 the head of a pin, it would look somewhat like the 

 eye of a beetle. Each eye of the Curculio contains 

 about 150 of these lenses. The number in the 

 eyes of butterflies, moths or dragonflies amounts 

 to many thousands. In some microscopic experi- 

 ments made lasrt summer upon the eyes of plant 

 lice from different trees and plants, it was found 

 that the number of lenses in the eyes of these in- 

 sects varied from every tree and plant. Each 

 thus proved to be a distinct species, no matter 

 how close the resemblance in other respects. Thus, 

 should the rose bushes of the garden or a neigh- 

 borhood be cleared of these pests they would not 

 be reinhabited by those from other plants. While 

 examining one of these aphides it brought forth 

 a young one, and this in turn being tested its eye 

 was found to contain the same number of lenses 

 as the mother's. This peculiarity of the eyes of 

 insects, and the knowledge of the exact number of 

 these lenses in the eyes of each species, become 



