September 7, 1906.] 



SCIENCE. 



309 



important in investigations where only the com- 

 minuted parts can be obtained. In a long series 

 of examinations of the contents of the stomachs 

 of birds, for the purpose of ascertaining more 

 positively how far the insectivorous kinds fre- 

 quenting orchards are useful in feeding upon these 

 enemies of fruits, the microscope has enabled me to 

 demonstrate many facts otherwise difficult to 

 prove (pp. 37-8). 



How lie made use of the little point about 

 the curculio he describes in a fascinating 

 manner : 



Killed an oriole (Baltimore) — a male of one 

 year; it did not have the brilliant colors of the 

 fully matured bird. I followed it from tree to 

 tree for a long time, listening to its peculiar notes, 

 and watching its habit of feeding. In a very 

 careful examination of the contents of the 

 stomach, what appeared to be the wing-cases of a 

 Curculio were discovered; and on further scrutiny 

 I found the head with proboscis attached. This 

 was exciting. Here was some evidence that one 

 bird at least was feeding upon our most formidable 

 insect enemy; but as the Curculio^ is one of a 

 large family of the Coleoptera, and many of the 

 different species bear a striking resemblance to 

 each other, both in form and size, it was neces- 

 sary to pursue the investigation still further. On 

 placing the wing cases under the microscope, the 

 peculiar protuberances — the brilliant metallic 

 colors — the hairs resembling pearls, when a strong 

 light is directed upon them, that I had so often 

 seen, were all visible. The mutilated head was 

 now tested. There was the proboscis with its 

 cutting apparatus, and the 147 lenses in the eye. 



I have examined the eyes of many others of this 

 family, but not one of them has the same number 

 of lenses. The larger species figured in PL 5, 

 Fig. 10, has more than double this number. 



All this evidence taken together was ample to 

 settle this question forever. The Baltimore eats 

 the Curculio I * Let the death of this martyred 

 bird secure the protection of its race for all future 

 time. The remains of three other beetles and 



^ His name for the curculio is Curculio argula 

 Fabr., which in modern terminology is Conotra- 

 chelus nenuphar. The larger species he mentions 

 is really on PI. VI., Fig. 10, and, he explains, was 

 figured from a specimen taken from the stomach 

 of a toad. From stomachs of these animals he 

 says he has often obtained different species of 

 beetles. 



* Now known to be eaten by many other species 

 of birds. 



three leaf-curling caterpillars " were also found in 

 the stomach of this oriole (p. 77). 



The Baltimore Oriole Eats the Curculio. Prob- 

 ably many other birds that frequent the orchard 

 in pursuit of food, and feed upon beetles do the 

 same thing; but none of them search it out ex- 

 clusively. Therefore, good as most of the birds 

 are as consumers of injurious insects, and though 

 the world, for our purposes, would soon become 

 topsy-turvy without them, the birds can not be 

 relied upon to subdue or control the curculio (p. 

 85). 



Here again our author gives an instance 

 that agrees with the results of a much greater 

 amount of study of the food of birds. That 

 is, birds simply act as a check upon insects, 

 sometimes as a minor one, sometimes the 

 chief. Such must always be the case, for ob- 

 viously no species can continue to exist if 

 it exterminates its food supply. 



Dr. Trimble found feathered enemies of an- 

 other great insect pest, the apple-worm, or 

 codling moth (Carpocapsa pomonella). This 

 is the very task at which an entire state (Cali- 

 fornia) set its energies. Indeed the little 

 codling moth demands a good share of the 

 attention of economic entomologists over the 

 whole world. Our author's efforts in search- 

 ing out birds that feed upon this insect are 

 particularly interesting. He treats the work 

 of the downy woodpecker in this direction in 

 detail and gives a plate (X.) in figuring this 

 bird, the yellow-bellied woodpecker and the 

 chickadee, so that any one, whether he be 

 acquainted with birds or not, can recognize 

 the friends and the supposed enemy. On the 

 same plate is shown some of the downy's work 

 — the exterior of a piece of bark with the little 

 round holes made by the bird's beak, and the 

 inner side of the same showing how straight 

 and true these tunnels were drilled through 

 to the chrysalis of the moth. He found them 

 at this work from September 8 (p. 135) to 

 April 21 (p. 115), and in his accounts of 

 every place he made observations, Dr. Trimble 

 mentions these holes in the bark of the apple 

 trees. Concerning a trip in Morris County, 

 N. J., he says: 



^ Tortricina. Also found by Dr. Trimble in the 

 stomachs of the wren and catbird. 



