INSECT FOOD. 



37 



species present May 28-30, 1896, after May-flies had become compara- 

 tively scarce. The soldier-beetles were in the grass, on blossoms, on 

 the foliage of bushes and trees, and in the air, yet of the 62 birds 

 collected, representing 19 species, only 3, namely, 2 wood pewees and 

 a phoebe, had eaten them. At other times (June, 1898 and 1899), when 

 the beetles were abundant, more than a hundred birds, including nearly 

 all the common species on the farm, were collected, and onl}^ a chat, 2 

 catbirds, and 2 kingbirds (June, 1898) had eaten them. Experiments 

 with several kinds of caged birds have shown that the species is dis- 

 tasteful, probably on account of its pungent and disagreeable flavor. 



Fireflies. — Another useful predaceous beetle of the same family, 

 having a similarly repulsive taste, is a firefly, Photluiis. In June it 

 sometimes, even during daylight, outnumbered the soldier-beetle, but 

 it was never found in stomachs of Marshall Hall lairds. 



Tiger-beetles. — The useful tiger-beetle, a ferocious predatory insect, 

 represented at Marshall Hall by several species, was never so numer- 

 ous as the soldier-beetle or the firefly, but was often seen by the dozen, 

 especially about the middle of April, in the sandy road along the bluflf. 

 It has no unpleasant flavor and must rely on its alertness to save it 

 from enemies. When danger threatens, it springs into the air and 

 flies swiftly away. Onl}" the quickest birds have any chance of catch- 

 ing it. A few birds, mainl}^ swallows and fl3^catchers, secure it occa- 

 sionall}^ Of the 61:5 birds examined only a phoebe, a kingbird, a 

 great crested flycatcher, and a crow blackbird had eaten it. 



Ground-beetles. — With ground-beetles (Carabidfe, fig. 12), which as a 

 class are regarded as predator}^, the case was differ- 

 ent. Most birds eat them, some species largely. 



Ground-beetles are numerous in spring, then be- 

 come less conspicuous, but appear later in large 

 numbers. Their period of greatest abundance in 

 the five years was April 10-14, 1899, when, with 

 the exception of ants, they were the most noticeable 

 insects on the farm. The smaller kinds {Anisodac- 

 tylus agricola^ A. ritsticus, Casnonia^ Amara^ and a 

 small Harpalus) predominated. Most of the birds 

 collected then were sparrows, which had eaten very 

 few of the beetles. At the same time the larvae of 

 a large ground-beetle {Ilarpahts callginosus) were fairly abundant, 

 and 4 of the 8 robins collected had destroyed them. During mid- 

 summer (especially 1898 and 1899) the large Carabidae {Harjxdus 

 callginosus and H. pennsylvcmicus) fairly swarmed after dark and were 

 attracted to lights in hosts. They were seldom seen during the daj^, 

 bat crows, blackbirds, catbirds, meadowlarks, and others frequently 

 extracted them from their hiding places. Three meadowlarks (August 



Fig. 12. -Ground-beetle 

 (after Riley; loaned 

 by Division of Ento- 

 mology). 



