298 BIRDS OF ILLINOIS. 



Nor is the Eose-breasted Grosbeak purely an ornamental bird. 

 On the other hand he is one of the most useful that we have as a 

 destroyer of noxious insects. In many parts of the Mississippi 

 Valley he is known as the "Potato-bug Bird," from the fact that he 

 is particularly fond of that most disastrous pest of the farmer. 



GENUS GUIRACA SWAINSON. 



Guiraca SWAINSON, Zool. Jour, iii, Nov. 1827,350. Type, Loxia ccerulea LINN. 



"GEN. CHAK. Bill very large, nearly as high as long; the culmen slightly curved 

 with a rather sharp ridge ; the commissure conspicuously angulated just below the nos- 

 tril, the posterior leg of the angle nearly as long as the anterior, both nearly straight. 

 Lower jaw deeper than the upper, and extending much behind the forehead ; the width 

 greater than the length of the gonys, considerably wider than the upper jaw. A promi- 

 nent knob in the roof of the mouth. Tarsi shorter than the middle toe ; the outer toe a 

 little longer, reaching not quite to the base of the middle claw; hind toe rather longer 

 than to this base. Wings long, reaching to the middle of the tail; the secondaries and 

 tertials nearly equal; the second quill longest; the first less than the fourth. Tail very 

 nearly even, shorter than the wings." (Hist. N. Am. B.) 



Guiraca ceerulea (Linn.) 



BLUE GEOSBEAK. 



Loxia ccerulea LINN. S. N. ed. 10, i, 1758,175; ed. 12, i,1766, 306.-WiLS. Am. Orn. iii, 1811,78, 



pi. 24, fig. 6. 

 Guiraca ccerulea SWAINS. 1827. BAHID.B. N. Am. 1858, 499; Cat. N. Am. B. 1859. No. 382. 



-B. B. & E. Hist. N. Am. B. ii, 1874, 77, pi. 29, flgs. 4,5.-EiDGW. Nom. N. Am. B. 1881. 



No. 246. COUKS, 2d Check List, 1882, No' 291. 



Fringilla ccerulea "!LL." LICHT. Preis-Verz. 1823,22. AUD. Synop. 1839,132. 

 Goniaphia ccerulea SCL. 1856. COUES, Key, 1872, 149; Check List, 1874, No. 195; B. N. W. 



1874, 169. 



HAS. Southern United States, from Atlantic to Pacific (very local, and irregularly dis- 

 tributed); north to Kansas, Illinois, Pennsylvania, and Connecticut (occasionally) or even 

 to Maine and Canada (accidentally). 



"Sp. CHAB. Brilliant blue ; darker across the middle of the back. Space around base 

 of bill and lores, with tail-feathers, black. Two bands on the wing across the tips of the 

 middle and secondary coverts, with outer edges of tertiaries, reddish brown, or perhaps 

 chestnut. Feathers on the posterior portion of the under surface tipped narrowly with 

 grayish white. Length, 7.25; wing, 3.50; tail, 2.80. 



"Female yellowish brown above, brownish yellow beneath; darkest across the breast. 

 Wing-coverts and tertials broadly edged with brownish yellow. Sometimes a faint 

 trace of blue on the tail. The young resembles the female. 



"Males from the Pacific coast region (California, Colima, etc.) 

 have tails considerably longer than eastern specimens, while those 

 from California are of a much lighter and less purplish blue, the 

 difference being much the same as between Sialia sialis and S. 

 azure a. 



