THE HONEY-GUIDES 



11 



in this character, the accompanying illustration (fig. 2) shows the 

 sterna of the eight species examined drawn as if they were the same 

 size. To keep these diagrams as simple as possible the processus 

 lateralis anterior has been left out in all cases. If we take the greatest 

 height (perpendicular) of the keel, and the total length of its base 

 to the tip of the manubrium, the former varies from 23 to 29 percent 

 of the latter in the species of Indicator' and Melichneiifes, while in 

 Prodotiscus it is 43 percent of the basal length . The degree of develop- 



a 



f 



Figure 2. — The sternum in eight species of honey-guides, all drawn to same size: a, Indicator 

 maculatus; b, Indicator variegatus; c. Indicator indicator; d, Indicator minor; e, Indicator 

 exilis; /, Indicator xanthonotus; g, Melichneutes robustus; h, Prodotiscus regulus. 



ment of the sternal keel does not appear to be correlated with observ- 

 able differences in flight as far as the honey-guides are concerned. 

 Certainly Prodotiscus does not give the impression of being a stronger 

 or more rapid flyer than Indicator, while the remarkable aerial evolu- 

 tions of Alelichneutes are produced by the species with the least 

 developed keel of all the members of the family. Parenthetically, 

 it may be remarked that when Sclater (1870, p. 178) described the 

 processus lateralis posterior and the processus intermedins as being 



