420 BULLETIN 17 6, UNITED STATES NATIONAL MUSEUM 



to the two mentioned, it sometimes prospected the exquisite tawny 

 flowers of the huge Opuntias near our camp site, but the bird seemed 

 to prefer those of the purple-bracted shrub, referred to above. 



"No larger than a huge orange-marked bee, which was intoxicated 

 by the same flowers, Atthis heloisa margarethae was not much larger 

 than its name on this sheet. Slower in its movements than the other 

 four hummingbirds, the revolution of its wdngs created only an 

 infinitesimal murmur. As compared with the energetic nervous 

 course of the white-ear, that of Atthis is slow and unwavering. It 

 resembles more closely that of the calliope than either of the other 

 two hummers. It is not nearly so swift as that of the broadtail. 



"In northwestern Mexico Margaret's hummingbird seems to be 

 confined to the Transition Zone, not descending very far below its 

 lower margin, as all of our specimens have come from 5,700 feet to 

 7,500 feet. Occasionally occurring elsew^here at lower levels, a female 

 was taken by Chester Lamb near the city of Tepic, Nayarit, at an 

 altitude of 3,000 feet. 



"I have no doubt that Margaret's hummingbird breeds in the 

 lower margin of the Transition Zone in Sinaloa, but we have never 

 found the nest." 



DISTRIBUTION 



Range. — Central Mexico south to Honduras; accidental in south- 

 ern Arizona; not generally migratory. 



The range of this species extends north to San Luis Potosi (Al- 

 varez) ; and central Veracruz ( Jalapa) . East to Veracruz ( Jalapa 

 and Cordoba) ; and Honduras (San Juancito). South to Honduras 

 (San Jauncito) ; Guatemala (Fuego Volcano and Atitlan) ; and 

 Guerrero (Omilteme). West to Guerrero (Omilteme), Mexico (Santa 

 Lucia) ; and southwestern San Luis Potosi (Alvarez). 



Casual records. — The only records for the United States are for 

 two specimens collected in Ramsay Canyon, in the Huachuca Moun- 

 tains, Ariz., on July 2, 1896. 



STELLULA CALLIOPE (Gould) 



CALLIOPE HUMMINGBIRD 

 Plate 70 

 HABITS 



This tiny mite is the smallest member of the group containing the 

 smallest North American birds. Grinnell and Storer (1924) state 

 that "its average weight is only about 3 grams (one-tenth of an 

 ounce) which is about half that of an Anna Hummingbird, or of a 

 kinglet or bush-tit." The length of the male is about 2% inches and 



