2l6 COIvORATlON IN I^KPTINOTARSA. 



The adults of almost all Leptinotarsa have strongly contrasting colors, and 

 are visible from a distance of many feet, often yards. For example, L. un- 

 decimlineata, with its white hypodermal color and deep, glassy greenish-black 

 markings, is an object which may be easily seen from a distance of from 30 to 

 40 feet, and often, when viewed from an elevation, for greater distances. It 

 stands out clearly and sharply against the green of its food plant, where it 

 lives boldly exposed upon the upper surface of the topmost leaves in a situa- 

 tion where it is at once recognizable and is most easily seen and attacked. The 

 photograph (plate 21, fig. i) shows the sharp contrast which this species 

 makes with its food plant, as also the total absence of even the most super- 

 ficial resemblance to any object in its environment which might afford it pro- 

 tection from its enemies. 



I have frequently taken a position in which I could observe a colony of un- 

 decimlineata in nature, and I have never seen one of them attacked at any 

 time of day by any of the insectivorous vertebrates. I have repeatedly seen 

 birds — tanagers, warblers, fly-catchers, etc. — visit the same branch upon 

 which the beetles were resting, and take other insects (Diabrotica, etc.), but 

 pass undecimlineata by. The same observations were made with reference 

 to several genera of Lacertilia. Additional evidence that they are not eaten 

 has been obtained by an examination of the stomach contents of insectivorous 

 birds, both diurnal and nocturnal, but no trace of these beetles was found 

 therein. Yet I have found, although rarely, mutilated specimens with the 

 elytra broken and the body crushed and torn, as if it had been picked up by a 

 bird or lizard and partly chewed, and then thrown away. These mutilations, 

 however, might have been due to injury from other causes, such as being 

 stepped upon by cattle or other large mammals, and can not be considered as 

 good circumstantial evidence of their being taken as prey by insectivorous 

 vertebrates and then rejected on account of some objectionable quality. 



Various insectivorous lizards and toads which have been confined in cages 

 with these beetles have rejected them as food. If, however, no other food is 

 provided and the starvation point is reached undecimlineata is eaten, and 

 without any apparent harm. This fact that under extreme shortage of food 

 lizards and toads eat these beetles is of absolutely no significance, because all 

 animals — even man — will eat anything under the conditions of starvation; 

 hence feeding experiments in zvhich the supposed objectionable food only is 

 supplied have no weight whatsoever against the idea of warning or protective 

 coloration. When a variety of food was supplied the toads and lizards passed 

 undecimlineata by unmolested, although other forms only a few centimeters 

 away were seized and eaten. I have frequently in nature seen lizards exam- 

 ine the beetles carefully, and then pass them by to take other food ; and I do 

 not think that there can be the least doubt that the conspicuous black and 

 white coloration of undecimlineata secures to it a high degree of immunity 

 from its enemies. 



