INTERDEPENDENCE OF ORGANISMS 



21 



Fig. T4. Diagram of head and pro- 

 boscis of a syrphus fly {Rhingia 

 nasicd). a. antenna; h, eye: c, 

 proboscis, with parts outspread; 

 h, its hinge . / its labellae. 



The coiled proboscis of moths and butterflies is the 

 most specialized of all, and limits its possessors to feeding on 



liquids. So slender as to be 

 filiform, coiling compactly like 

 a watch spring beneath the 

 head, and extending when un- 

 rolled to a length sometimes 

 exceeding the length of the 

 body, it is adapted for reach- 

 ing the nectar in the deepest 

 corollas, and for entering 

 the narrowest passageways. 

 Moreover, it is most unique 

 in structure in that it con- 

 sists of the laciniae of the two maxillae only, these be- 

 ing elongated, channelled within and closely applied 

 together to form a tube. The only other mouthparts 

 that are well developed in the commoner butterflies and 

 moths are the labial palpi, 

 which project forward from 

 beneath the head, and be- 

 tween which the proboscis 

 coils itself up when at rest. 

 So greatly have the mouth- 

 parts been modified that 

 the identity of them in their 

 present condition would 

 not be recognized by a 

 beginner; the accompanying 

 diagram (fig 15), of a speci- 

 men cleaned of the scales which densely cover the ves- 

 tigial organs, indicates all the parts by name. 



The jointed proboscis of the Hemiptera is relatively 

 unimportant in nectar feeding. It is rather adapted for 



Fig. 15. Diagrams of 

 head and mouthparts 

 of a butterfly a, 

 side view of head, 

 with proboscis partly 

 uncoiled; b, oblique 

 view of face, denuded 

 of scales; /, labrum; 

 md. mandible ;^, rudi- 

 mentary palpus of 

 maxilla; x, proboscis, 

 composed of con- 

 .loined laciniae of 

 maxillae: i, labium, 

 with the large ter- 

 minal joint of the 

 proximal palpus re- 

 moved. 



