54 



NORTH AMERICAN FAUNA. 



The following measurements give the averages of the two forms: 

 Measurements of Plranga bldentata and Piranga b. Jlammea. 



Hirundo erythrogaster Bodd. Barn Swallow. 



Soon after our arrival on Maria Madre a few swallows, supposed to 

 be this species, were seen by my assistant, but none were taken. They 

 were undoubtedly stray migrants, for none were seen afterwards. 



Vireo flavoviridis forreri (Madarasz). Ferrer's Vireo. 



Vireo forreri Madarfisz, Term&jzetrajzi Fiizetek, IX, pt. I, p. 85, 1885. 



Although Ferrer's vireo is one of the most abundant and widely dis- 

 tributed species on the islands, yet it does not appear in Gray son's 

 list. It was very common in the small trees in the patio of the custom- 

 house and elsewhere about the settlement on Maria Madre. Like its 

 mainland relative, its habits are very similar to those of the red eyed 

 vireo. Its favorite range was in the smaller growth of forest along the 

 lower slopes, from near the sea up to an altitude of 600 or 700 feet, but 

 some were seen up near the summits of Maria Madre and Maria 

 Magdalena. Next to the Tres Marias warbler, Ferrer's vireo was prob- 

 ably the most abundant bird on Maria Madre, and its restless habits 

 while fluttering and peering about in search of food among the small 

 tree tops added greatly to the animation of the forest. 



Vireo forreri is evidently only a geographical race of Vireo flavor i- 

 ridis. It has the same color pattern, but the ashy crown is paler and 

 the dusky supraorbital stripe usually obsolescent ; the latter is one of 

 the main characters upon which forreri was originally based, but is not 

 constant. Some specimens from the islands have this stripe as strongly 

 marked as dull-colored individuals of flavoviridis proper, although none 

 have it so strongly marked as some of the latter. The two forms are 

 alike on the underparts, and the greater size of forreri is the most 

 constant and striking character. 



Average measurements of 17 adult males of Vireo flavomridis forreri: 

 Wing, 84.3; tail, 59.3; culraen, 15.1; tarsus, 20.1. Averages of Vireo 

 flavoviridis (from mainland of Mexico): Ad. $ (9 specimens), wing, 79.2; 

 tail, 55.1; culmeu, 14.3; tarsus, 18.7. Ad. 9 (3 specimens), wing, 76.C; 

 tail, 50.6; culmeu, 14.1; tarsus, 18.5. 



Vireo hypochryseus sordidus Nelson. Tres Marias Vireo. 



Vireo liypochryseus Grayson, Proc. Boston Soc. Nat. Hist., XIV, p. 281, 1871 ; Lawr., 



Mem. Boston Soc. Nat. Hist., II, p. 272, 1874. 



Vireo hypochrysfus sordidus Nelson. Proc. Biol. Soc. Washington, XII, p. 10, 1898. 

 A few of these vireos were seen in the thin forest on the lower slopes 

 of Maria Madre, but were not common. They were especially numer- 





