452 NORTH AMERICAN lURDS. 



cuntiiiiiud two cgjijs, exactly resembling those of the T. cohibris, and measur- 

 ing .")! by .'.VI of an inch. 



Ai'terwards Mr. W. W. Holden obtained a specimen in the Colorado Val- 

 ley, March 20. 



Ml'. J. K. Lord, one of tlie English commissioners of the Northwestern 

 J)0nndary Survey, met with this si)ecies near ins camping-place on the west- 

 ern slope of the liocky ^Mountains. This was near a lake, by the margin of 

 u-hicli, with otlier trees, grew a niuuber of the black birch. On tiiese trees 

 he found a sweet gunnny saj) exuding plentifully from splits in the bark, 

 and on this iap hosts of insects, lirgc and small, were regaling themselves. 

 As the sap was very sticky, numbers of the smaller winged in.sects were 

 trapi)ed in it. Busily emiiloyed in picking off and devouring these captive 

 insects were .several very sondire-looking Humming- Bird.s, poising them- 

 selves over the tiower.s, and nipping off, as with delicate forceps, the im- 

 prisoned insects. Upon securing f)ne of these birds, he ascertained that it 

 belonged to this si)ecies. 'Hiis was ])retty satisfactory proof that they are 

 insect-eatei's. Xot only on this occasion, lint many times afterward.?, JMr. 

 Lord saw tiiis liird ])ick tlie insects from the tree; and the stomaclis of those 

 he killed, on l)eing open(Ml, were filled with various kinds of winged insects. 

 He found this l)ir(l lingering around lakes, ])ools, antl swami)s, where these 

 birches grow. Tliey generally liuild in the birch or aider, selecting the fork 

 of a brancii liigh up. 



Tiiis species bears a very close resemblance in size, appearance, and niark- 

 ing.s, to tiie comnu)n eastern .species, but is readily distinguishable by the 

 difference in the color of the chin and tiie .sliape of the tail. 



In the sjjring of LS.'il, on a trij) to Sonora, :M('xico, Dr. Heermann found 

 tliese iiirds al)undant in the arid country around (Juaymas, where amid the 

 scanty veg('tation they had constructed their nests in the month of A])ril. 

 lie also afterwards found them on Dry Creek and the C'l.suiunes Itiver. 



According to the ob.srrvations of Mr. liidgway, this species has ([uite an 

 extended distribution in tin! West. He fo-md it in vaiying abundance from 

 tiie Sacramento Valley, in California, to the Wahsatch and Uintah Moun- 

 tiiins in I'tah. 



At Sacnimento it was more aliuiulaiit tlian the C. anna, nesting in tlio 

 door-yards and in gardens, but particularly in tlie thick copses (.f small oaks 

 in the outskirts of the city. In the (Jreat Dasiii it associated witli the 

 Sc/(isp/iurHs riifiis in tiie western portion, and with ,S'. p/itfi/mri'n to the east- 

 ward, nesting ev(!ry where, from the lowest valleys to a height of eight or 

 nine tii(jusaiid feet in tiie inountahis. 



