National Museum, 6; Philadelphia Academy, 4; New York Museum, 1; Cambridge Museum, 1; Cab. G. N. Lawrence, 1; R. Ridgway, 3. Total, 16. _Measurements._ +----+-----------+-----------+---------+---------+-----------+----------+ |Sex.| Wing. | Tail. | Culmen. | Tarsus. |Middle Toe.|Specimens.| +----+-----------+-----------+---------+---------+-----------+----------+ | ♂ |10.60–11.85| 6.00–6.80| .60–.65|1.35–1.55| 1.00–1.10| 6 | +----+-----------+-----------+---------+---------+-----------+----------+ | ♀ |11.30–12.30| 6.50–7.00| .60–.65|1.30–1.40| 1.00–1.05| 5 | +----+-----------+-----------+---------+---------+-----------+----------+ HABITS. This Hawk appears to be confined to the extreme southern and southwestern portion of the Gulf States. It is not known to occur farther north than South Carolina on the Atlantic, though on the Mississippi it has been traced much farther north. It is most abundant about the Mississippi. It was first discovered by Wilson near Natchez, where he found it quite abundant. Mr. Say afterwards observed it far up the Mississippi, at one of Major Long’s cantonments. On Captain Sitgreave’s expedition to the Zuñi and Colorado Rivers, it was found to be exceedingly abundant in Eastern Texas, as well as in the Indian Territory, more particularly on the Arkansas River and its tributaries. Dresser states that he found this Hawk by no means an unfrequent bird in Texas, and generally in the same localities with the _Nauclerus forficatus_. It was not very common near San Antonio, but was occasionally found, and even breeds there, as he procured both the old and the young birds during the summer. In travelling eastward in the month of May, he first noticed them near the Rio Colorado, and was told by the negroes on one of the plantations that they were then nesting. On the 20th of May he shot a female on the banks of that river, from which he extracted a fully formed egg. It was almost round, and rather large for the size of the bird. Eastward from the Colorado he also saw this Hawk quite often. [Illustration: _Ictinia mississippiensis._] Though the species, no doubt, occurs in Mexico, Mr. Sclater states that all the Mexican _Ictiniæ_ which he has seen, collected by Sallè, Boucard, and others, have belonged to _I. plumbea_ (Ibis, 1860, p. 104). A single specimen from Coban, Central America, was obtained by Mr. Salvin, but _I. plumbea_ was by far the most common species of _Ictinia_ in Vera Paz.