PROTECTION FROM UNWELCOME VISITORS 427 



Sometimes the recurved petals or divisions of the corolla 

 stand in the way of creeping insects. In other cases the throat 



FIG. 320. Branching hairs from the outside of the corolla of the 



common mullein 



Magnified. After Tschirch 



of the corolla is much narrowed or closed by hairs, or by ap- 

 pendages. Those flowers which have one or more sepals or 

 petals prolonged into spurs, like the nasturtium and the colum- 

 bine, are inaccessible to most insects except those which have 



FIG. 327. A sphinx moth, with a long sucking tube 



a tongue or a sucking tube long enough to reach to the nectary 

 at the bottom of the spur. The large sphinx moth, shown in 

 Fig. 327, which is a common visitor to the flowers of the 



