ascertained to occur in Illinois. 391 



Family PLOTEID^. The Aohingas. 



Genus Plotus, Linnaeits. 



291. P. an?dnga Tu i n n . Snake-bird ; Darter. Summer sojourner in 

 extreme soutlieru portion; rare summer visitant uortli to 38° 30'. 



Order LONGIPENNES. 



Family LARID^. 



Subfamily Larin^e. The Gulls. 



Genus Larus, Linnaeus. 



Subgenus Larus. 



292. L. marinns li inn. Black-backed Gull. " Saddle Back." Win- 

 ter visitant ou Lake Michigan (Dr. Velie). 



293. L. argentatus Briiuii., var. Smithsonianus Coues. Herring 

 Gull. Winter sojoui-ner; occasional in summer? 



294. L. Delawarensis O r d . King-billed Gull. Winter sojourner. 



Subgenus Chroicocephahis, Eyton. 



295. G. Philadelphia (Ord). Bonaparte's Gull; Little Black-headed 

 Gull. 



296. C. FranMinii {R\c\i.). Franklin's Rosy-breasted Gull. Winter 

 visitant to northern portions. 



297. C. atricilla (Linn.) Laughing Gull. Summer visitant. 



Subfamily Sternin^. The Terns. 

 Genus Sterna, Linnaius. 

 Subgenus Thalassetis, Boie. 



298. S. caspia Pall., var. imperator Coues. Caspian Tern. Win- 

 ter visitant to northern part. 



299. 8. rerjiaGr a, inh . Royal Tern ; Cayenne Tern. Summer visitant 

 throughout the state. 



Subgenus Gelochelidon. 



300. S. anrjlica Mont. (var. " aranea W i 1 s ."). Marsh Tern. Sum- 

 mer visitant to Lake Michigan. 



Subgenus Sterna, Linnaeus. 

 *301. S. hirundo Linn. Common Tern; Wilson's Tern. Sum- 

 mer sojoui'ner in northern portion. 

 *302. S. For steri 'is nit. Forster's Tern. Summer sojourner. 

 * 303. 8. antillarum (L e s s.). Summer sojourner. 



