1NSECTA. 



235 



rule given above, is not only furnished with rudimentary wings, 

 but is eminently rapacious, and possesses in the structure of its 



Fig. 103. 



mouth, to be described hereafter, peculiar facilities for gratifying 

 its blood-thirsty disposition. 



In other orders, the wings are always unequal ; the pos- 

 terior, and sometimes both pairs, not unfrequently being wanting. 



. Mouths adapted to sucking. 



5th Order. Diptera* Instead of posterior wings, we find in 

 this order pedunculated appendages called halteres orpoisers. The 

 mouth contains a soft proboscis, and is usually armed with several 

 setse and provided with a pair of palpi ; of such, the common 

 house-fly affords a familiar instance. 



6th Order. Lepidoptera.^ The insects belonging to the lepi- 

 dopterous order are possessed of four wings, which are generally 

 covered with microscopic scales, frequently exhibiting the most 

 beautiful colours : the larvae are provided with feet and a dis- 



* ^iTTi^os (S/-j, wrigflv), with two wings. "T X /?, a scale 



