THE MEXICAN BEAN BEETLE ^ 



By W. H. White 

 Bureau of Entomology and Plant Quarantine, United States Departme7it 



of Agriculture 



[With 6 plates] 

 INTRODUCTION 



In 1920 a black-spotted copper-colored beetle was discovered on 

 garden beans in the vicinity of Blocton and Birmingham, Ala. It 

 was readily recognized by the entomologists as an insect known at 

 that time as the bean lady-beetle, an immigrant from the West, an 

 immigrant w-hose presence was viewed with alaim because the in- 

 sect had been long recognized as a destroyer of garden beans in the 

 irrigated regions of the southwestern States. As early as 1883 

 Prof. G. H. Stone of Colorado Springs, Colo., in a letter to C. V. 

 Riley, Entomologist of the United States Department of Agricul- 

 ture, dated August 26 stated: 



By this mail I seud you a tin box containing larvae and perfect beetles 

 which promise to have almost as unenviable a reputation as Doryphora 10 lineata 

 [the Colorado potato beetle which spread across the country from the West 

 toward the East and destroyed the potato crop during the period of from 1824 

 to 1874]. From the egg to the grave they are voracious. They are good judges 

 of food. With me they have confined their attacks to black wax beans, and 

 the enclosed leaves and pods will show their mode of attack. The early 

 broods attack nearly all kinds of vegetables in a neighboring garden. They 

 are rapidly spreading in the vicinity. I judge there are two or three broods 

 in the year like Doi-yphora— they only appeared in my garden a few days ago. 

 Within that time they have eaten almost every leaf in a good sized patch of 

 wax beans. 



Stone's letter to Eiley was apparently not the first record of the 

 occurrence of the bean beetle as a destroyer of beans as F. H. Chitten- 

 den, of the United States Department of Agriculture, quotes a letter 

 from a correspondent from the West, dated 1889, in which it is 

 claimed that the beetle "had been known by its ui juries at Watrous, 

 N. Mex., 40 years earlier than the date of writing." This date, being 

 close to the Mexican War of 184&-48, led Chittenden to conjecture 



* Epilachna varivestis Mills. 



343 



