182 life, IN ITS intermediate forms. 
shaped that the hind pair seem as if cut out of the fore 
pair, with which they interlock by means of small hooks 
during flight, so that both might readily be mistaken for 
a single pair. Tho nervures are commonly stouter, and 
form a wider network, and the membrane is generally less 
delicate than in the preceding Order. 
All the forms of Insects which we have been enume- 
rating agree in one point, viz., that their mouth is fur- 
nished w T itli biting jaws ; thoso that follow, on tho other 
hand, have the same organs, but so modified in develop- 
ment and altered in function as to constitute a sucking, 
pumping, or piercing apparatus. The elegant Lepidop- 
tera, or Scale-wings, including the Butterflies, which are 
active by day, the sonorous-winged Hawkmoths, that 
probe tubular flowers in the twilight, and the Moths, 
which swarm in the early hours of night, constitute the 
next order. Their chief peculiarities have been already 
mentioned, and we shall therefore merely mention the 
Silkworm, the caterpillar of an Oriental moth, now natu- 
ralised throughout the civilised world, as another example 
of an Insect to which man is largely indebted. 
An extensive group is called Hemiftera, or Half-wings, 
because the majority of them have the fore- wings curiously 
varied in texture, tho basal portions being of a stiff leathery 
consistence, while the terminal part, separated from the 
former by an abrupt lino, is thin and mombranous. The 
vast tribe of Bugs comes here, all of them repulsive and 
disgusting from their rank pungent odour, but in many 
cases adorned with rich colours, and often bearing tho 
most bizarre forms. Here, too, are usually placed, though 
distinguished by some entomologists, the insects which 
