302 
HALF IIOUES WITH INSECTS. [Packard. 
insects belong to the lowest division of the winged insects, 
and, even geologically speaking, to a very ancient stock. It 
is significant to find developed in them such a high degree 
of architectural skill. 
The mechanical ingenuity of the case worms is shown in 
the construction of their cases. These are ancient types of 
insect forms thought to be in some respects similar to those 
occurring in the coal formation, while undoubted caddis- 
flies occurred in the Wealden strata of the Lower Creta¬ 
ceous formation. Sir Charles Lyell assures us that “ a large 
species of caddis-worm, which swarmed in the Eocene lakes 
of Auvergne in France, was accustomed to attach to its 
dwelling the shells of a small spiral univalve of the genus 
Paludina.” It must have resembled the cases of the British 
Limnophilus jiavicornis , w r hose case (Fig. 232) is covered 
with little fresh water snail shells. Other 
examples of the work of these interesting 
insects are given on page 132. They 
gather bits of leaves or sticks, or particles 
„ of gravel, with their jaws, and arrange 
them around their body, covering their 
hind body first and then building on to the anterior end, 
gluing the particles together by means of a silky secretion. 
They probably do not use their fore legs in this process, at 
least the- clothes moth does not in constructing a similar 
case. Other cases are made by rolling up a strip of leaf 
deftly cut out of the required length and width, as seen in 
Fig. 92, while others, more careless, attach broad, irregular 
pieces to their cases. 
Another net-veined insect which shows much ingenuity in 
the construction of its dwelling, and much low cunning in 
providing itself with food, is the ant lion. This is the larva 
of the Myrmeleo. Its body is broad and flat, armed with 
enormous scissor-like jaws which project straight out from 
the head. It lives in colonies, sometimes numbering 
14 
over 
