161 



In making a study of the food of (he Pilot in rehition to the time 

 of year in which it wa^ taken, we observe that during the early part 

 of the summer the predominating feature consists of eggs or young 

 birds, and thus at this time of year it is economically objectionable; 

 (see Food Chart 12 B) while during the latter part of the summer it 

 consists to a great extent of mice and other obnoxious mammals, 

 (see Food Chart 12 C) and from the economic standpoint at this time 



Fig- 12a. — Diag'iam bnovvmg the percentages of 

 Food Items of Pilot Snake {Callopeltis ulixaletufi) : 

 liy2 per cent. Red Squirrels; 2 per cent. Oppossum; 

 28 per cent. Birds; 2 per cent. Birds' Eggs (Un- 

 determined); 41/^ per cent. Weasels; 10 per cent. 

 Meadow Mice (Microtus pennsylvanicus) ; 2 per 

 cent. Hens' Eggs; 21 per cent. Insects (Probabb'' 

 from Birds); 7 per cent. Undetermined Mammals; 

 12 per cent. Mice (Undetermined). 



of year it is to be considered as beneficial. It is impossible to strike 

 a balance and say that this creature is so objectionable from an 

 economic standpoint as to deserve destruction, nor so beneficial 

 at all times as to justify preservation. We can only indicate what 

 we have found and say that further studies are necessary before 

 final conclusions are to be reached. 



No. 13. Callopeltis vulpinus (B. & G.) Fox Snake. 



The Fox Snake is so called because of its light brown color, and 

 while it is more or less common and in some of the northern states, 

 it is not a common species in I*ennsylvania. It is given as a Penn- 

 sylvanian species upon the authority of Jordan, and is recorded 

 as occurring from Massachusetts to Kansas and northward. Thus 

 11 



