37° 



CHARACTERS OF INVERTEBRATE ANIMALS 



-S5e-[ 



<^^ 



during flight. In the present order the same end is brought 

 about by a more perfect contrivance. On the front margin of 

 the hind-wing, which is smaller than the fore-wing, a series of 

 hooks will be found which catch on to a fold on the hinder 

 margin of the latter, and due to a curling up of the edge. The 

 complex mouth-parts are adapted for both biting and licking, as 

 may be seen by careful examination of a hive-bee (fig. 223). 



The triangular upper lip will here be 

 seen to overlap a pair of powerful man- 

 dibles, under which come the long first 

 maxillce, provided with cutting- blades 

 and palps (in this species very small), and 

 lastly follow the fused second maxillce. 

 These are drawn out into a slender 

 tongue-like structure suited for licking, 

 and grooved for the conduction of liquid. 

 Female Hymenoptera are either pro- 

 vided with a sting at the posterior end of 

 the body, or else with a piercing arrange- 

 ment (ovipositor) for making holes in 

 which to lay the eggs. The m,etamor- 

 phosis is particularly well-marked. Larvae 

 resembling caterpillars, or it may be of 

 worm-like appearance, hatch out from 

 the eggs, which have previously been 

 deposited in plants, the bodies of other 

 insects, or sometimes in specially-con- 

 structed chambers (as in bees). The pups are generally enclosed 

 in a cocoon of silk, and, as in beetles (see p. 366), their limbs 

 project freely. 



Three sub-orders are recognized: — i. 

 Eaters, and 3. Stinging Hymenoptera. 



I. Plant -Eating Hymenoptera include the Saw -Flies and 

 Wood-borers, of which some thousand species have been described. 

 The ovipositor of the female is adapted for boring holes in plants, 

 and the abdomen does not in either sex narrow to a stalk at its 

 base, as in a wasp or ant. The mouth-parts are not so specialized 

 as in the example taken above. The larvae resemble caterpillars, 

 for which indeed they are often mistaken, but may easily be dis- 

 tinguished by the presence of more than five pairs of pro-legs in 



Fig. 223. — Structure of Hymenoptera 



A, Wings of a bee. b, Diagram of mouth- 

 parts of Honey-Bee {^Apis nieilifica), much 

 enlarged and widely separated. 



Plant- Eaters, 2. Insect- 



