2 BULLETIN 841, IT. g. DEPARTMENT OF AGRICULTURE. 



chance to feed upon the various cultivated plants grown in bulk by 

 the farmer or gardener, many of these insects gradually desert their 

 native host plants and to a greater or less degree change their habits, 

 including in their fare the more succulent and easily found food. 



HISTORY 



The existence of the western grass-stem sawfiy was first made 

 known in 1890 when Mr. Albert Koebele reared adults from larvae 

 that were mining in the stems of native grasses growing in the vicinity 

 of Alameda, Calif. 1 During the next year, 1891, the species was 

 described under the name of Cepltus occidentalis by Messrs. Riley and 

 Marlatt, from a series of individuals reared by Mr. Koebele and also 



Fig. 1.— Western grass-stem sawfiy ( Ccphus ductus): Adult female. Much enlarged. 



from co types that had in the meantime been collected in Nevada 

 and Montana. 2 In connection with this description the prophetic 

 suggestion was made that: "The economic importance of this species 

 arises from the fact that it may be expected at any time to abandon 

 its natural food-plant in favor of the small grains, on which it can 

 doubtless successfully develop." 



Nothing more w T as heard of this sawfiy until 1S95, when the late 

 Dr. James Fletcher, Entomologist to the Dominion of Canada, swept 

 adults at Indian Head, Northwest Territories, on July 5. He believed 

 it to belong to the European species, Cejplius' pygmaeus L., and under 



i Koebele, A. Notes. In V. S. Dept. Agr. Div. Ent. Insect Life, v. 3, p. 71, 1890. 

 2 Riley, C V., and Marlatt, C L. Wheat and Grass Saw-Flies. In U. S. Dept. Agr. Div. Ent. Insect 

 Life, v. 4, p. 168-179, 1891. (See p. 177-178.) 



