io OUR INSECT FRIENDS AND FOES 



It is particularly interesting to note, for instance, 

 that the minute cavities between the "touch- 

 hairs " have been observed to be more abundant 

 in male insects, and particularly in those species 

 where the females are hidden and have to be 

 sought out by the males. 



The wings, normally four in number, are 

 always placed upon the upper surface of the 

 thorax, and are thin, more or less transparent 

 expansions of the integument supported by 

 branching ribs or nervures. The opaque cha- 

 racter of the wings of most Butterflies and 

 Moths is due to their being covered with 

 numerous overlapping, microscopic scales of 

 various colours. In the Beetles and Locusts, 

 the posterior wings are membranous, while the 

 anterior pair are hard, tough cases, called elytra, 

 and which, when folded up, cover and protect 

 the delicate posterior wings. In the true Flies 

 (Diptera) the anterior wings are.alone developed ; 

 knobs, or club-shaped structures called the hal- 

 teres or balancers, representing vestiges of the 

 posterior pair. In the Lice (Pediculidce), Spring 

 Tails (Thysanurd), and Fleas, wings are entirely 

 absent at all stages of the insect's development. 



On the ventral surface of each of the three 

 segments of the thorax of an insect will be 

 found a pair of legs, varying in size, strength, 

 and shape according to the habits and mode of 

 life of the insect, and composed of six to nine 

 joints. The terminal part of the leg, which is 

 called the tarsus, is composed of a number of 

 short segments, and ends in a pair of claws, 

 varying considerably in shape and size in 



