112 USEFUL BIRDS. 
caterpillars (Leucarctia acrewa), the caterpillar of the vaporer moth 
(Orgyia) and the spiny larve of butterflies; with these perhaps may 
be classed the European currant sawfly. He was disposed to consider 
the “flavor of all these caterpillars as nauseous, and not that the 
mechanical troublesomeness of the hairs prevents their being eaten. 
Larvee which spin webs, and are gregarious, are eaten by birds, but not 
with avidity ; they appear very much to dislike the web sticking to their 
beaks, and those completely concealed in the web are left unmolested. 
When branches covered with the web of Hyponomenta evonymella (a 
little moth of the Tinea family) were introduced into the aviary, those 
larye only which ventured beyond the protection of the web were eaten.” 
* Smooth-skinned, gaily colored caterpillars (such as the currant Abraxas 
or spanworm), which never conceal themselves, but, on the contrary, 
appear to court observation,” were not touched by the birds. He states, 
on the other hand, that “all caterpillars whose habits are nocturnal, 
and are dull colored, with fieshy bodies and smooth skins, are eaten with 
the greatest avidity. Every species of green caterpillar is also much 
relished. All Geometrs, whose larve resemble twigs, as they stand 
out from the plant on their anal prolegs, are invariably eaten.”! 
Such statements as these are at least interesting, but they 
noust be classed as negative evidence, and cannot justify the 
assertions so often made that_birds do not eat hairy cater- 
pillars, when there is convincing, positive evidence that cer- 
tain species do eat them. This statement that birds do not 
eat. such caterpillars, which has been so long reiterated, 
parrot-like, by one writer after another, is entirely at variance 
with my experience, and my opportunities for investigating 
this subject probably have been better than those of most 
observers. The great burden of proof is upon those who 
make the allegation, for it is always hard to prove such 
sweeping generalizations, and often not at all difficult to dis- 
prove them. A naturalist may with propriety say what he 
has seen a bird do, but he should be cautious in stating what 
it does not do. The reiterated assertion that hairy cater- 
pillars are immune from the attacks of birds has been modi- 
fied of late by some writers, and is now oftener given, in 
effect, that few birds eat them; but this statement needs still 
further modification. We cannot rely on results secured by 
First Report on Injurious and Beneficial Insects of Massachusetts, by A. S. 
Packard. Annual Report of the Massachusetts State Board of Agriculture, 
1870-71, pp. 358, 359. 
