THYSANUKA. 
25 
These little creatures are in several genera covered with 
scales of various forms and sizes, generally colourless > 
but sometimes beautifully 
iridescent, as in the genus 
Lepidocyrtus. These scales 
are favourite microscopic 
objects. Besides scales, hairs 
of various forms clothe the 
bodies of these little insects. 
The young are hatched ap¬ 
parently within a period of 
from six to ten days, the 
larvae are white and very 
active in their movements ; 
I have seen hundreds of 
them under rotten bark in 
damp places. The Collembola 
undergo no metamorphosis. 
The young differ from the 
adults merely in being 
shorter and thicker, and 
having the spring-tail less 
developed; after moulting 
twice the white larval body 
becomes of the same colour 
as that of the adult, purplish 
and translucent. 
The Thysauura are much 
less numerously represented 
both in species and indi¬ 
viduals than the Collembola ; the body consists of th 
head, three thoracic and ten well-marked abdominal 
-a 
lepisma saccharine. Spring-tail (Podura plumbea). 
