68 
HALF HOURS WITH INSECTS. [Packard. 
distinguish them apart, as an enemy of our comfort or 
crops. 
Moreover there are insects which are friendly in but a Pick¬ 
wickian sense. There are certain parasitic insects that stick 
to us closer than a brother, and yet with the moral qualities 
of fiends. Man is a sort of treasury or bank to these crea¬ 
tures — and they are happily few in number — who “ draw” 
upon him not only “ at sight,” but who “ go it blind.” And 
when through carelessness or idleness the bank is too attrac¬ 
tive and liberal in its discounts, the audacious vermin congre¬ 
gate in teeming hosts, and make “ a run” upon it. Parasitic 
insects seem in many cases to be actually blind through ava¬ 
rice, as amaurosis is not an uncommon affection 
among articulated parasites. It would seem as 
if the gods struck blind all such beings for their 
greed in sucking our blood. 
There is the louse (Fig. 54), the most intimate 
of tlrnse friends, forsooth, of ours. Ugly and 
repulsive in itself y it is tenfold more so in its 
associations. Though its legs are well devel¬ 
oped, the beak wonderfully adapted for its use, 
yet it lives in a Stygian twilight, its ej^es re¬ 
duced to a simple point, a little depression on 
the side of its head forming but a single isolated facet, the 
simplest kind of eye, when there are 25,088 such facets in 
the eye of a certain small beetle (Mordella) and 4000 in 
that of the house fly, whose head is all eyes. If we look 
at the beak of the louse (Fig. 55) we shall at once perceive 
that the creature does not bite, but that it in reality sucks 
our blood; so the mosquito introduces its blade-like jaws 
and sucks our blood. It is incorrect to say that a mosquito 
bites. Those organs that in allied insects are jaws, in the 
lice lose their biting function and are converted into a fleshy 
extensible tube, the true jaws forming ribbon-like bands 
strengthening the tube. 
fig. 54. 
Louse. 
4 
