The fleas (Fig. 81), which are often included in the 

 Diptera, are sometimes considered as a distinct order. They 

 differ from the other Diptera in being wingless, and in the 

 structure of the larva. They agree in the complete meta- 

 morphosis and in the sucking mouth parts. 



Order X. Hymenoptera. The Membrane-winged 



Insects. 



The order includes such well-known insects as the bees, 

 wasps and ants, and an enormous number of very small and 

 inconspicuous insects which are highly beneficial from their 

 habit of living parasitically in or upon other insects. The 

 members of this order (Figs. o2 and 33) possess two pairs 

 of membranous wings, and there is generally a distinct con- 

 striction between the thorax and abdomen ; sometimes, as in 



Fig. 32. Hymenoptcra. Carpenter bee. 

 Slightly reduced. (Original ) 



Fig- 33- Hymenoptera. Leaf cutting bee. 

 A bout \\ times natural size. (Original.) 



