U. S. D. A., B. K. Bui. t;i, Part V. 



Issued Miiv29, VMS. 



SOME MISCELLANEOUS RESULTS OE THE WORK 

 OE THE BUREAU OE ENTOMOLOGY-LX. 



INSECTS INJURIOUS TO THE LOCO WEEDS. 



P.y F. II. ('hittkni)en, Sc. 1 ).. 

 Kntoinnlof/isl in Vlmrfic of Jirccdiiu/ J-Jd/XTimcnts. 



For many years the Bureau of Entomology' has conducted corre- 

 spondence in regard to insects found on the loco weeds of tlie semi a rid 

 regions of the West. In earlier 3'ears these insects were found chiefly 

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

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

 stockmen that tlie 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 weeds have 

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

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

 stroj^er 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. Ixecenth' Dr. C. Dwight JVIarsh, 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 spotted root fly.^' Of these the root-maggot, midge, and root 

 fly are prol)ably 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 observations, after the phiut has pro- 

 duced its quota of seed. 



The following account of loco insects has bi'en i)re])are(l fi-oui the 

 records of the Bureau of P^ntomology. uiuch of the matei-ial having 

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



" WnlftJiin nniorphdla CUmh. 

 ^ thrill ra iitroiistdns Fitch. 

 '^ PcffO))nj(i liipini Coq. 



^Clronim qiindrilincdtu.-t riicvr. 

 '^ Euxcsta notaia Wiod. 



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