WINGS AND MOUTH-PARTS. 



FIG. 8. 



Fit/, to skotv the second pair of wings 

 reduced to balancers. 



In distinguishing- the different classes of insects, it is necessary to 



look specially at the wings and the 

 mouth-parts. In mature insects 

 there are, as a rule, two pairs of 

 wings : the first pair (upper or fore- 

 wings) attached above the second 

 pair of legs, the second (lower or 

 hind wings) attached above the 

 third pair of legs. In some insects 

 the second pair of wings is not 

 present or is transformed into 

 a different structure. In a few 

 the wings are never developed, 

 the mature insect being wing- 

 less or having imperfectly de- 

 veloped wings. (Figs. 16, 30, 40 

 and 51.) 



The " mouth-parts " (jaws) of insects are the structures that surround 

 the mouth and which are used for feeding. These structures are somewhat 

 complicated and are specially formed in accordance with the habits of the 

 insects. Insects that 

 bite leaves or green 

 plants have short bit- 

 ing mouth-parts, with 

 cutting teeth; insects 

 that attack other 

 insects have usually 

 long sharp jaws, suit- 

 ed for grasping their 

 prey ; those which 

 suck the juice of 

 plants have a slender 

 tube-like beak, with 

 sharp instruments for 

 piercing the plant ; 

 those also which suck 

 the blood of animals 



or insects have a sharp tubular beak, as in the mosquito. It is important 

 to be able to recognise the differences between these kinds. A few have 

 mouth-parts not included in either of the above kinds ; thus the bees have 

 very complicated jaws, which are fitted for lapping up the nectar in 



FIG, 9. 

 Head of a Caterpillar, from beneath. 



