INTRODUCTION. 
18 
two-winged insects have a pair of small knob-like 
threads behind the anterior pair of wings; they have 
been termed Jialteres or balancers, and are generally 
regarded as the rudiments or representatives of the 
hind wings. Mr. Lowne is inclined to think that the 
function of these modifications of the posterior wings 
is auditory; he imagines he has discovered within 
them certain corpuscular bodies, which he considers 
to be otoconia. The membranous wings of butterflies 
and moths are covered with numerous flattened scales 
of various forms and exquisite beauty ; hence the name 
of the order Lepidoptera from rig a scale, and 
wing; while those of many others are simply clothed 
with numerous small hairs. 
The abdomen, as has been said before, consists of 
nine segments, but these are not always distinct; it is 
regarded as consisting of two portions, the abdomen 
proper, and the post-abdomen, the latter of which is 
supposed to be marked by indications of three segments 
between the generative outlet and the terminally 
situated anus. The abdomen proper never carries 
articulated appendages, with—so far as is known at 
present—the single exception of the Spirachtka Eury- 
medusa , a beetle, which carries a pair on the third, 
fourth, and fifth abdominal segments; the post- 
abdominal segments, however, frequently carry ap¬ 
pendages, as the thick bristles of the cockroaches, the 
tubular appendages of the aphides, the forceps of the 
earwigs. 
The organs of motion are localized in the thorax, the 
vegetative in the abdomen. 
The accompanying woodcut will give the reader a 
