Contents xiii 



PAGE 



of solitary wasps, 491. Velvet -ants (Mutillidae), 497. Cuckoo-flies (Chrysididae), 

 498. Mason- or potter-wasps, 498. Eumenidae, 498. Digger-wasps (Sphecidae, 

 Larridae, Bembecidae, Pompilidae), 499. Wood-mining wasps (Mimesidae, Pem- 

 phredinidae, Crabronidae), etc., 502. Social wasps (Vespidae), 503. Key to 

 genera, 503. Life-history of community of yellow-jackets, 503. Bees, 510. 

 Characteristics, 511. Solitary bees, 513. Mining-bees and carpenter-bees, 513. 

 Mason-bees and potter-bees and leaf -cutters, 514. Mining-bees, 516. Social 

 bees, 517. Bumblebees, 517. Honey-bees, 520. Life-history of community, 521. 

 Ants (Formicina), 533. Characteristics and life-history, 535. Key to families, 

 540. Poneridae, 540. Myrmicidae, 541. Camponotidae, 545. Artificial nests, 

 548. Myrmecophily, 552. Problems of ant behavior, 554. 



CHAPTER XVI 



INSECTS AND FLOWERS 562 



Relations between plants and insects, 562. Cross-pollination in flowers, 563. 

 Means of avoiding self-fertilization, 565. Specialization for cross-pollination, 

 566. Uses of nectar and odor, 567. Modifications of insect visitors, 569. Par- 

 ticular cases of flower specialization for cross-pollination, 571. Tubular corollas, 

 571. Irregular tubular flowers, 572. Cross-pollination in Asclepias, 573. 

 Cross-pollination of Araceae and Aristolochiaceae, 575. Cross-pollination of 

 orchids, 575. Cross-pollination of Yucca by Pronuba, 576. Origin of speciali- 

 zations for cross-pollination, 579. 



CHAPTER XVII 



COLOR AND PATTERN AND THEIR USES 583 



Wide distribution of color and pattern among insects, 583. Explanations of 

 some color phenomena in insects, 583. How color in organisms is produced, 

 586. Classification of insect colors, 587. Color patterns of the butterflies and 

 moths produced by scales, 589. Characteristics of the scales, 589. Ontogenetic 

 appearance of color pattern in insects, 596. General protective resemblance, 599. 

 Variable protective resemblance, 599. Special protective resemblance, 602. 

 Warning colors, 604. Terrifying appearances, 605. Directive coloration, 607. 

 Mimicry, 608. Criticisms of hypotheses of color use, 6n. 



CHAPTER XVIII 



INSECTS AND DISEASE 615 



Economic relations between insects and man, 615. Dissemination of human 

 diseases by insects, 616. Mosquitoes and malaria, 617. Mosquitoes and yel- 

 low fever, 630. Mosquitoes and filariasis, 632. 



CHAPTER XIX 



REFLEXES, INSTINCTS, AND INTELLIGENCE 635 



Theories of insect behavior, 635. Points of view of Loeb and Jennings; tro- 

 pisms and method of trial and error, 635. Distinguishing among reflexes 



