THE MONTH! J Y BULLETIN. 



33 



THE MEXICAN BEAN WEEVIL. 



By Ei>w. O. Amundsen. 



A Mexicuii l)can ]\llo^vll as "Guaiinichile" (pi-oiiimiK-cd wha-moo- 

 chile), is often found infested by a weevil, Bruchus limhatus. Fig. 15. 



The bean is "hot," as indicated by the ending, "ehile. " It is flat, 

 hard, black and ii'lossy. inoa.siu'es al)ont three-eighths of an ineh in diam- 



FiG. 15. — The Mexican bean weevil, Bruchus 

 limbatus ; a, dorsal view; b, ventral view. 

 Nine times enlarged. (Original.) 



eter, and is rather irregularly shaped (Fig. 16). The bean is com- 

 pletely enveloped in a yellowish, oily pulp which is eaten raw by the 

 natives with evident relish. This covering of pulp is shown in Fig. 16. 



Fig. 16. — Tlie Guamucliile bean: a, infested beans re- 

 . moved from tlie pulp ; b, sliowing the oily, yellowisli pulp 

 whicli envelops the bean. Natural size. (Original.) 



The pn1i)-eov(n'od beans are borne in pods, which are four to six inches 

 long, five to eight beans in a pod. (Fig. 17.) 



The weevil, Bruchus limha(us, is found in seeds of other legumes and, 

 if unchecked, renders tliciii unfit for food or seed. Even though the 

 weevils are killed, the iMnl)ryo of the seed is in many cases devoured by 

 the larva and consequently does not germinate. 



