U. S. D. A., B. E. Bui. 64, Part V. tsBOed May 29. 191 8. 



SOME MISCELLANEOUS RESULTS OF THE WORK 

 OF THE BUREAU OF ENTOMOLOGY-IX. 



INSECTS INJURIOUS TO THE LOCO WEEDS. 



By F. H. Chittenden, Sc. I)., 

 Entomologist m Charge of Breeding Experiments. 



For many years the Bureau of Entomology has conducted corre- 

 spondence in regard to insects found on the loco weeds of the semiarid 

 regions of the West. In earlier years these insects were found chiefly 

 on purple or woolly loco. Astragalus mollissimus, and more recently 

 on the white loco, Arag alius lamberti. It was at one time supposed by 

 stockmen that the insects might be the cause of the poisoning to sheep, 

 cattle, and other stock, but such is not the case. 



The general subject of loco poisoning to stock has been treated in 

 various publications, but the insect inhabitants of the Aveeds have 

 never received mention in this connection, with the exception of the 

 false-indigo gall-moth, which is apparently the principal insect de- 

 stroyer of the loco. Numbers of correspondents and observing bota- 

 nists have noticed that the caterpillar of this insect, which feeds at the 

 roots and crowns of locos, is quite instrumental in reducing their abun- 

 dance. Recently Dr. C. Dwight Marsh, Bureau of Plant Industry, 

 has collected many insects on locos and expresses the opinion that sev- 

 eral other species are concerned in this work. Chief among these are 

 the fickle midge, 6 the loco root-maggot , c the four-lined loco weevil,'' 

 and the spotted root fly. 6 Of these the root-maggot, midge, and root 

 fly arc probably In the main attracted to the plants after the gall- 

 moth has first caused injury, but the weevil also attacks living root-. 

 usually, however, according to observations, after the plant has pro- 

 duced its quota of seed. 



The following account of loco insects has been prepared from the 

 records of the Bureau of Entomology, much of the material having 

 also been supplied by Doctor Marsh, and in the list which follows it 



" Walshia amorphella (Mem. *Cleonus quadrilineatus Chow. 



b Sciara inconstans Fitch. e Euwesta notata Wied, 



Pegomya lupini Coq, 



33 



