CARNIVOROUS INSECTS 103 



B. Mouth more or less perfectly suctorial (in the adult). 



6. MOTHS AND BUTTERFLIES (LEPIDOPTERA). 



7. FLIES AND FLEAS (DIPTERA). 



8. FRINGED-WINGED INSECTS (THYSANOPTERA). Corn-Thrips, &c. 



9. BUGS (HEMIPTERA). 



The above grouping is founded on the structure of the mouth- 

 parts in the adult, but these may be quite different in the larva, 

 in correlation with different habits. A caterpillar, for example, 

 has biting mouth-parts, but the corresponding organs of the moth 

 or butterfly into which it ultimately develops are purely suctorial. 



MEMBRANE-WINGED INSECTS (HYMENOPTERA) 



This order is regarded by many authorities as the highest 

 among insects, not so much perhaps on the ground of complexity 

 of structure as on the score of a marvellously-developed intelli- 

 gence, seen more particularly in the social species of ant, bee, 

 and wasp. Details relating to the social economy of such forms 

 will be given in another connection, when the association of 

 animals is considered ; here we are only concerned with the 

 question of food. Ordinary British species are omnivorous in 

 habit, but certain tropical forms show a marked predilection for 

 animal food, and some of them migrate from place to place in 

 formidable armies which make a clean sweep of everything that 

 comes in their way. 



PREDACEOUS ANTS. This is the case, for instance, with the 

 much-dreaded Driver- Ants (Anomma arcens) of West Africa, 

 regarding which not a few unpleasant stories are current, such 

 as the reported tying-up of criminals in their path and so forth. 

 Their habits have been described by Savage, who states that 

 they check " the more rapid increase of noxious insects and smaller 

 reptiles; consume much dead animal matter, which is constantly 

 occurring, decaying, becoming offensive, and thus vitiating the 

 atmosphere, and, which is by no means the least important in the 

 Torrid Zone, often compelling the inhabitants to keep their 

 dwellings, towns, and their vicinity in a state of comparative 

 cleanliness. The dread of them is upon every living thing . . . 

 Their entrance into a house is soon known by the simultaneous 

 and universal movement of rats, mice, lizards, Blapsidae, Blattidae, 

 and of the numerous vermin that infest our dwellings." These 



