I'. S. It. A.. B. K. Hul. CI, Part V. Issued May 19. I'.i S 



SOMH MISCHLLAXEOUS RESULTS OF THE WORK 

 OF THE BUREAU OF ENTOMOLOGV-L\. 



INSECTS INJURIOUS TO THE LOCO WEEDS. 



r.y 1". II. Chittendkx, Sc. D., 

 KntontolDjii.st in Cliarf/c of Brerdiii;/ IJ-ritcriinents. 



For many years the Bureau of Entomology has conducted corre- 

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

 I'egions of the AVest. In earlier years these insects were found chiefly 

 on purple or woolly loco, Astragalus niolUsslmus, and more recently 

 on the white loco, Aragallus lamherti. It was at one time supposed by 

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

 cattle, aiid 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 weeds have 

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

 false-indigo gall-moth," which is apparenth" 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 

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

 (hmce. Kecently 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,'' the loco root -maggot,'" the four-lined loco weevil,"^ 

 and the si)otted root fly.*' Of these the root-maggot, midge, and root 

 fly are probably in the main attracted to the plants after the gall- 

 moth has first caused injury, but the weevil also attacks living roots, 

 usually, however, according to ol)servations, after the phmt ha- pro- 

 (hiced its (juota of .^eed. 



Tile following account of loco insects has been i)re])ar(Ml from the 

 i('co!-(ls of the Bureau of Entomology, much of the material ha\iiig 

 •d-o been supplied by Doctor Marsh, and in the list which follow.^ it 



" M'alftJiia fniioriiJiflla Cloni. ^Clcoiiiiss qitadriliiinifiift Chow. 



>> Scinni iiicDiistinis Fitch. '^ Eiucstn in/tatn Wicd. 



"" l'( (imniid hiiiiiii <'n(i. 



33 



