1092 REPORT OF STATE GEOLOGIST. 



taken near Brookville, Ind. Two additional nests were built upon the 

 original structure, burying beneath each the egg of a Cowbird (Molo- 

 thrus ater). Thus it outwitted the detestable parasite, and in the 

 third nest deposited her complement of eggs. Similar nests have been 

 found elsewhere, showing that this was not an individual peculiarity, 

 but others of its kind had experimented along the same line. 



Prof. F. H. King examined eleven specimens, which he found had 

 eaten 22 case-bearing caterpillars (Coleophora ?), 5 other larvae (2 of 

 them caterpillars), 6 small dragon flies, 3 moths, 3 dipterous insects, 

 3 very small hymenopterous insects, 3 beetles (among them a squash 

 beetle), 3 spiders, 2 small grasshoppers, 1 leafhopper, 2 hemipterous 

 insects, and 2 insect eggs (Geol. of Wis., I., p. 508). As a result of 

 such examination as has been made, it seems that the prevailing Yel- 

 low-throat in Indiana is the Maryland this bird. Mr. Robert Ridg- 

 way informs me that the Maryland Yellow-throats in the Smith- 

 sonian collection from Indiana (Wheatland and Vincennes) are either 

 true 0. trichas, or else that form approaching G. t. occidentalis. More 

 recently I have sent him a series of Yellow-throats, containing speci- 

 mens from Indiana, northern Illinois, Jamaica and the Valley of 

 Mexico. All of these, after comparison, he decides to refer to G. 

 trichas. He adds: "The Mississippi Valley birds and those from 

 Mexico (valley) are in reality intermediate between trichas and occi- 

 dentalis." 



*288. (681a). Geothlypis trichas occidentalis BREWSTER. 



Western Yellow-throat. 



Similar to G. trichas, but averaging larger; the lower parts, yellow 

 and not part whitish. 



Length, 4.75-5.85; wing, 2.10-2.40; tail, 2.15-2.40; bill, .40-.45: 

 tarsus, .75-.S3. 



RANGE. Western North America, from Central America and west- 

 ern Mexico over western United States to Manitoba and British Co- 

 lumbia, east to Illinois and Indiana. 



Nest and Eggs as in last species. 



The Western Yellow-throat is a summer resident, like the last, 

 wherever found. I am informed by Mr. Eliot Blackwelder and Mr. 

 J. G. Parker, Jr., that this is the prevailing form in Cook County, 111., 

 and the last named gentleman says it is the same in Lake County, Ind.. 

 where he has taken specimens at Liverpool. Mr. Parker says it is 

 abundant in low ground bordering our marshes and along the banks 

 of our creeks and rivers. Arrives May 1 to 15. It is possible that 

 the form inhabiting the prairie districts may be found to approach 

 more closely to this bird. 



