GENE E A AND SPECIES. 



Genus HELIACTIN, Boie. (Les Queues etroites, 

 Lesson, Cynanthus, in part, Swainson). 



In this genus the beak is rather short and 

 spiny. In the male the head is ornamented 

 with a long aurifulgent crest overhanging the 

 eyes and ears ; the throat is adorned with a 

 dusky black gorget, free, and pointed, drooping 

 on the chest ; the tail is graduated, and consists 

 of long narrow pointed feathers, all white, except 

 the two central. 



The female wants the splendid head-crest, 

 but is otherwise very beautiful. 



One species only is as yet recorded, viz. Tro- 

 chilus cornutus, described and figured, male 

 and female, in the Naturalist's Lib. Ornith. 

 vol. i. p. 122, pi. 21 ; p. 124, pi. 22. 



Locality : Brazil. 



Genus THATTMASTUBA, Bonaparte, (Calothorax 

 and Mellisuga, in part, Gray) 



The type of this genus is the Trochilus Cora 

 of Lesson, described as the Cora Humming-bird 

 in the Naturalist's Lib. Ornith. vol. i. p. 129, 

 pi. 25. It is remarkable for the graduation of 

 the tail, and the length of the two central tail- 

 feathers. 



Locality : Peru. In Gould's cabinet. 



The Prince of Canino places within this genus 

 the Trochilus Vesper of Lesson , but it is not 

 strictly typical. It is described as the Evening 



