1904.] PACKARD— ORIGIN OF MARKINGS OF ORGANISMS. 427 



conditions on the elevated plateau of Mashonaland? As to the sup- 

 posed resemblance of the Pimplae with dark barred wings, do they 

 not bear quite as close a resemblance to Panorpa? 



^'Miillerian mimicry in South African beetles, etc.," is further 

 illustrated by PI. XIX, with fifty-nine excellent colored figures. 

 The first sixteen figures represent ** a powerful group of Cantharidae 

 and the insects convergent toward them, and having conspicuous 

 cream, orange or red bands on a black ground." In reflecting on 

 the causes of this similarity in coloring of Ethiopian Cantharidae, 

 Mylabris, etc., it occurs to one that in the humid and cool climate 

 of the northern United States the species of Cantharis are black or 

 gray, in the southwestern States and Territories that they become 

 gray and spotted, in southern Europe the typical species is of a 

 brilliant rich green, but not banded or spotted, while in Africa, 

 with its torrid heats, these beetles though of differing genera are 

 banded, or run into secondary forms in which the bands are broken 

 into spots. Is there not here a direct and controlling relation to 

 the climatic conditions, i.e., heat and heat-loving habits, elevation, 

 moisture or dryness? Whatever the style of coloration, they all 

 secrete from the waste products of the blood a bitter vesicant 

 pigment, by which the individuals are protected, whatever be their 

 color, by their more than disagreeable taste and after effects. 



In this plate a number of Hemiptera, yellowish or reddish banded 

 with black, somewhat resembling the beetles, are introduced, but 

 they are themselves distasteful and sufficiently protected unless very 

 unlike their congeners known to be such. 



The markings of beetles of various other families, Coccinellidse, 

 Chrysomelidae and Cerambycidae, some distasteful, others innocuous 

 or neutral, are evidently the result of convergence, and the more 

 such examples are multiplied the stronger is the case for conver- 

 gence. 



In the last figures (53-59) are blackish ants, with shades of red- 

 dish, Megapetus atratus, a hemipter, and a Myrmecophana} fallax, 

 a cricket-like form. Now there is at first sight a general resem- 

 blance to the ants on the part of these hemipterous and orthopterous 

 mimickers, but this is due to the loss of wings by disuse, the result 

 of lack of exercise in flight, a cause vastly more thoroughgoing and 

 transforming than the good or bad taste of the pigment. 



Again, take the case of Belt's Nicaragua frog. All the frogs 

 observed by Belt, with this one exception, are like those in all other 



