410 
PODURA. 
On the ground its legions, on a cursory view, have 
the appearance of scattered grains of gunpowder; 
and, if closely examined, will be found in an al- 
most continual skipping motion. 
Podiira Jimetaria so perfectly resembles the pre- 
ceding in all respects except colour, being per- 
fectly white, that no other specific dilference can 
be observed. It is almost equally common in 
damp situations with the former, 
Podura atra is of a short, subglobular shape, 
with lengthened antennre: its colour is a glossy 
black: it is found on the bark of trees, &c. &c. 
Podura plumbea is of a blueish black or deep 
lead-colour, and is found in similar situations. 
Podura arborea is of a lengthened form, and 
of a black colour, with the feet and caudal fork 
white. It is chiefly found on tlie bark of trees, 
among mosses, &c. &:c. 
