REPORT ON SOME PARASITIC AND PREDACEOUS DIPTERA 

 FROM NORTHEASTERN NEW MEXICO. 



By W. R. Walton, 



Of the Bureau of Entomology, United States Department of Agriculture. 



The diptera noted and described in this paper were all collected in 

 Colfax County, New Mexico. With but few exceptions, they were 

 taken during the latter half of July and the first half of August, 1913. 

 The work was undertaken in connection with an investigation of the 

 New Mexico range caterpillar {Hemileuca olivix Cockerell) at present 

 being carried on by the United States Department of Agriculture, 

 Bureau of Entomology, under the immediate supervision of Prof. 

 F. M. Webster, expert in charge of cereal and forage insect investi- 

 gations. 



The purposes of these collections were: First, to ascertain what 

 species of parasitic diptera are present throughout the area most 

 infested by Hemileuca with a view to their utilization in the combat 

 against this insect. Second, to facilitate the determination of such 

 parasitic or predaceous diptera as may be used for experimental 

 purposes in the range caterpillar investigations. The camp estab- 

 lished for this latter project was used as a base of operations for these 

 collections. This is situated on the open mesa and located about 18 

 miles almost due south of Raton, directly on the old "Santa Fe trail.'' 1 

 Three miles to the westward, the foothills of the Sangre de Cristo 

 Range of the Rocky Mountains rise abruptly to a height of from 1,500 

 to 2,000 feet above the plains. From thence westwardly, a con- 

 tinuous series of benches rises one above the other until the main 

 range is reached, some 60 or 70 miles distant. 



The valley is bounded on the north by the Raton Range and par- 

 tially inclosed to the eastward by more or less isolated peaks rising to 

 a height of 2,000 or 2,500 feet above the plains, which are said to lie at 

 an elevation of about 6,500 feet, sea level datum. Several of the 

 peaks are surrounded by extensive mesas, the level of which lie at an 

 elevation of from 500 to 1,000 feet higher than the surrounding plain 

 and possess a rather abundant vegetation. 



One of these, namely, that of Eagle Tail Mountain, was explored 

 and collections made. The insect fauna of the entire region worked 



Proceedings U. S. National Museum, Vol. 48-No. 2070. 



171 



