An article at Futility Closet reprints an awesome 1910 Strand magazine feature: "If Insects Were Bigger." Basically, the authors inserted closeup pictures of insects into idyllic Edwardian street scenes. My favourite detail is the man brandishing his walking stick at the enormous creature:Fig. 1: A Lacewing Fly Spreads Consternation in Wellington Street.
The author of the original article ends with the following thought-provoking insight:
"It is true we are still molested by hordes of wild animals of bloodthirsty propensities. These wild animals only lack the single quality – namely, that of size – to render them all-powerful and all-desolating, and this quality they have not been able to attain owing to the lack of favouring conditions."
The pedant in me is obligated to point out that the scenario envisaged by the Strand author - that is, the growth of houseflies the size of camels and grasshoppers the size of passenger aircraft - is physically impossible. It's not just a matter of a "lack of favouring conditions"; the fact is that a housefly simply can't be scaled up to that size and still support its own weight. Suppose that all its dimensions were increased by a factor n; its volume would thus increase by n^3 (ie: cubed), which would mean that its mass would also be cubed. All this extra mass, however, is still supported by its spindly insect legs, whose cross-sectional area has increased by the factor n^2 (ie: squared). As the insect becomes larger and larger, the difference between n^2 and n^3 would become larger and larger, until finally its limbs become completely unable to hold up its body and the creature is unable to move. The same logic applies, of course, to its wings and every other organ in its body. An insect could never reach the size depicted above without massive physiological changes that would make its appearance unrecognizable.
That's what the pedant in me says. Mostly, I just think giant insects would be awesome.
(h/t Wondermark. Does everyone read this webcomic already? If not, you should.)