INSESSORES. 527 



Humming-birds are pre-eminently South American, but extend 

 northwards as far even as the southern portions of Canada. 

 The bill (fig. 227, E) is always very long and slender, as are 

 the toes also. The tongue is bifid and tubular, and appears to 

 be used either to catch insects within the corollas of flowers, 

 or to suck up the juices of the flowers themselves. The plu- 

 mage of the males is always brilliant, with metallic reflections, 

 that of the female generally sombre. The legs are short and 

 weak, but the wings are proportionately very long, and the 

 flight is exceedingly rapid. 



The Sun-birds represent in the Old World the Humming- 

 birds of the western hemisphere, and the Australian Honey- 

 eaters show also many points of resemblance to the Tro- 

 chilidcE. 



Sub-order 4. Fissirostres. In this sub-order of the Inses sores 

 the beak is short but remarkably wide in its gape (fig. 227, F), 

 and the opening of the bill is fenced in by a number of bristles 

 (vibrissa). This arrangement is in accordance with the habits 

 of the Fissirostres, the typical members of which live upon 

 insects and take their prey upon the wing. The most typical 

 Fissirostral birds, in fact, such as the Swallows and Goat- 

 suckers, fly about with their mouths widely opened ; and the 

 insects which they catch in this way are prevented from escap- 

 ing, partly by the bristles which border the gape, and partly by 

 a viscid saliva which covers the tongue and inside of the mouth. 



The typical Fissirostres, characterised by this structure of the 

 beak, comprise three families the Swallows and Martins 

 (Hirvndinida), the Swifts (Cypselidce), and the Goat-suckers 

 {Caprimulgida). These three families differ in many important 

 respects irom one another, but it would be inconvenient to 

 separate them here. The Swifts, especially, are remarkable 

 for the peculiarity that whilst the hallux is present, it is turned 

 forwards along with the three anterior toes. The Goat-suckers, 

 again, hunt their prey by night, and they are provided with 

 the large eyes and thick soft plumage of all nocturnal birds. 

 Besides the above, there remain the two families of the King- 

 fishers and Bee-eaters, which are generally placed amongst the 

 Fissirostres, though in very many respects the arrangement 

 appears to be an unnatural one. These families are charac- 

 terised by their stronger and longer bills, and by having the 

 external toe nearly as long as the middle one, to which it is 

 united nearly as far as the penultimate joint. In consequence 

 of this peculiar conformation of the toes, these families were 

 united by Cuvier into a single group under the name of 

 Syndactyli. 



