586 PROr. E. B. POULTON : NATURAL SELECTION 



the buzz, in tlie movements of the body (the latter being such as 

 to suggest the power of stinging), and (in the mimicry of hairy 

 humble-bees) in the acquisition of an abundant hairy covering. 

 A good example of a fairly perfect resemblance is shown in 

 Plate 41. fig. 5 a, an Australian fly, the models from the same 

 part of the world being shown in figs. 5 B and 5 c. 



A Hemipterous insect requires the most profound modification 

 Iq the shape of its flattened un-wasp-like body, and in the dis- 

 play and characteristics of its wings. Corresponding to these 

 much greater initial differences, the resemblance is onuch rarer 

 than in Diptera. A beautiful instance is shown in Plate 41. 

 fig. 1, a Hemipterous insect — a species of Myocoris, probably 

 M. hraconiformis (Burm.) — which is extraordinarily like fig. 2, 

 not, in this instance, a wasp but an ichneumon, using the term 

 in the broad sense ; for the species belongs to the Braconidce and 

 is probably an Iphiaulax. Although the two specimens in the 

 "British Museum, which I have been kindly permitted to figure, 

 did not come from the same part of S. America (the Bug was from 

 Para, the Ichneumon from Ega), the resemblance is so close in 

 every way and the modification of the Hemipteron so extreme 

 and remarkable, that there can be little doubt as to this being 

 a genuine case of mimicry and as to the geographical coincidence 

 of the model and mimic : both may have a far wider range than 

 is shown by the specimens which have been figured*. 



A Lepidopterous insect requires above all to gain trans- 

 parent wings, and this in the most striking cases that have been 

 studied is produced by the loose attachment of the scales, so that 



* Since the above sentence was written I have searched the collections in the 

 British Museum for further examples, with the help of Sir George Hampson, 

 Mr. C. J. Gahan, and Mr. W. F. Kirby. We found that the type of appear- 

 ance represented in Plate 41. figs. 1 and 2 is common and widely distributed in 

 S. America, forming a group which includes many species of Braconidce and of 

 Hemiptera which resemble them. Many figures of such insects presenting 

 this type of appearance are to be seen in the plates of the ' Biologia Oentrali- 

 Americaua.' In the distasteful group of moths, the Syntomidce, two species are 

 obviously similar, viz., Leucotmemis varipes (Walk.) from Para, and L. tenthre- 

 doides (Walk.) from Ega. Myocoris hraconiformis is recorded from Surinam as 

 well as from Para. 



The co-existence of species of Aculeate Hymenoptera, Hemiptera, and 

 distasteful Heterocera, suggests that the group as a whole is distasteful or 

 specially protected, and is an example of common warning colours. Many 

 other members of the group will probably be recognized 



