LONG-LEGGED TERN. 
Gelochelidon nilotica macrotar sa (Gould) ; Australia (breeding). 
This form was first described in the Synops. Birds Austr., and the head figured. 
The description reads : — 
St. vertice et nucha nigris ; corpore supra primariisque argenteo-cinerascentibus ; 
partibus reliquis corporis albis ; rostro pedibus que nigris. 
Long. tot. 16 unc., rostro 2^, alae 12, caudae 5^ tarsi If. 
Crown of the head and back of the neck black ; all the upper surface and primaries 
light silvery-grey; Ijhe remainder of the plumage white; bill and feet black. 
This subspecies differs in its more powerful and longer bill, its longer legs, 
its long wings, its lighter coloration above, and its white tail. This is a most 
distinct form to have suffered lumping. 
Gelochelidon nilotica addenda, subsp. n. ; China (breeding). 
This form approaches nearest to the North American it its short bill, but it 
is stouter in this form, and the stoutness in conjunction with its shortness, 
gives it an unmistakeable appearance. Measurements of culmen 36-37 mm., 
wing 310. The coloration of the tail is lighter than that of the back, showing 
an approach to the preceding form. 
Gelochelidon nilotica grdnvoldi, subsp. n. ; South America (breeding). 
The birds from South American breeding-localities are separable from North 
American birds by their longer bills and longer wings. The measurements 
of the culmen are 42-45 mm., wing 325. 
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