ADAPTIVE COLORATION 189 



the many other instances in which stinging Hymenoptera are counter- 

 feited by harmless flies or beetles. A locustid of the Soudan resembles 

 an ant (Fig. 246), and the resemblance, by the way, is obtained in a 

 most remarkable manner. Upon the stout body of this orthopteron 

 the abdomen of an ant is delineated in black, the rest of the body being 

 light in color and inconspicuous by contrast with the black. Indeed 

 the various means by which a superficial resemblance is brought about 

 between remotely related insects are often extraordinary. 



Irrespective of affinity, insects of diverse orders may converge in 

 wholesale numbers toward a central protected form. The most com- 

 plete examples of this have been brought to light by Marshall and 

 Poulton, in their splendid work on the bionomics of South African 

 insects, in which is given, for instance, a colored plate showing how 

 closely six distasteful and dominant beetles of the genus Lycus are imi- 

 tated by almost forty species of other genera a remarkable example of 

 convergence involving no less than eighteen families and five orders, 

 namely, Coleoptera, Hymenoptera, Hemiptera, Lepidoptera and Diptera. 

 Excepting a few unprotected, or Batesian, mimics (a fly and two or 

 three beetles), this association is one between species that are already 

 protected, by stings, bad tastes or other peculiarities. In other words, 

 here is Miillerian mimicry on an immense scale; and if Miillerian mim- 

 icry is profitable when only two species are concerned, what an enormous 

 benefit it must be to each of forty participants! 



Strength of the Theory. Evidently the theory of mimicry rests 

 upon the assumption that the mimics, by virtue of their mimicry, are 

 specially protected from insectivorous foes. Until the last few years, 

 however, there was altogether too little positive evidence bearing upon 

 the assumption itself, though this was supported by such scattered ob- 

 servations as were available. The oft-repeated assertion that this lack 

 of evidence was due simply to inattention to the subject, has been proved 

 to be true by the decisive results recently gained in the tropics by several 

 competent investigators who have been able to give the subject the 

 requisite amount of attention. 



From his observations and experiments in India, Frank Finn con- 

 cludes: 



"i. That there is a general appetite for butterflies among insec- 

 tivorous birds, even though they are rarely seen when wild to attack 

 them. 



"2. That many, probably most, species dislike, if not intensely, at 

 any rate in comparison with other butterflies, the warningly-colored 



