Vol. 34, pp. 63-66 March 31, 1921 



PROCEEDINGS 



OF THE 



BIOLOGICAL SOCIETY OF WASHINGTON 



FOOD HABITS OF SCELOPORUS GRACIOSUS GRACI- 

 OSUS (BAIRD AND GIRARD). 



BY HERBERT J. PACK. 



A few years ago the writer collected about seventy specimens 

 of the common sagebrush swift, Sceloporus graciosus graciosus 

 (Baird and Girard) for a study of its food habits. The stomach 

 contents of these lizardsh ave been examined and the results 

 are tabulated below. Most of the lizards were taken on the 

 foothills northeast of Salt Lake City, while a few were secured 

 in the western part of the city and ten miles to the north in 

 Bountiful. All were taken in the month of August, except as 

 noted in the following table. This is a numerical, not a per- 

 centage, table. 



The examination of the stomach contents thoroughly substantiated the 

 common beHef that this Hzard is insectivorous and beneficial. The chief 

 item of food was found to be the red-legged locust, Melanoplus femur- 

 rubrum. This was the smallest and most abundant grasshopper in the 

 localities from which lizards were collected. It is surprising to note the 

 great number of lizards, 69 per cent, that had eaten one or more of these 

 locusts. The next insects in importance were ants. In quantity these are 

 relatively unimportant in comparison with grasshoppers. Among the few 

 beneficial insects eaten must be mentioned lady beetles which were taken 

 to a limited extent by 11 per cent of the lizards. The occurrence within a 

 stomach of vegetable matter or grains of sand was only occasional, and 

 undoubtedly was taken in accidentally with food. 



These brief observations remind one of the fact that in the scheme of 

 nature this hzard occupies a place of no little importance. 



12— Proc. Biol. Soc. Wash., Vol. 34, 1921. (63) 



