Gnats

after Robert Hooke, Micrographia (1665)

Their world is a glass of rainwater.
They move up and down through the clearness,
   swallowing their way,
or hang by their tails from the surface:

tiny transparent caterpillars
with their bristled segments of body,
   horned trophies of head.
The glass holds nothing that I can see,

but they find matter to eat in it,
which pulses through a black thread of gut.