MEXICAN" BEAN BEETLE IN THE SOUTHEAST. 27 



frugiperda S. & A. A fourth collected in the field proved to be 

 Eelioihis ohsoleta Fab. (PI. XI, C.) These unusual habits may have 

 been caused by the destruction by the bean beetle of the bean foliage 

 on which these insects had been feeding. 



The ants Solenopsis geminata Fab. and Pheidole sp. destroyed bean- 

 beetle pupae in experimental cages during the summer of 1921. 



The adult of Epilachna corrupta has been observed to feed on its 

 own eggs in the field in the presence of green bean foliage, and 

 larvae have also been observed feeding on pupae in the presence of 

 other food, but very rarely. In the absence of green foliage, adults 

 and larvae very commonly feed on pupae and eggs of the bean beetle, 

 but not to a sufficient extent to be important in natural control. 



Not infrequently dead larvae and pupae, light brown to dark brown 

 in color, are observed in the field, attached to leaves. Bacteriological 

 examinations of such specimens by Dr. G. F. White showed the 

 presence of unidentified Coccobacillus and Streptococcus. Attempts 

 to inoculate healthy larvae by spraying cultures, furnished by Doctor 

 White, on bean plants exposed to the larvae availed nothing. It 

 appears, however, that in the field during the summer a low percentage 

 of larvae and pupae succumb to a bacterial disease. 



PARASITES. 



The Mexican bean beetle has been exceptionally free from parasites 

 in the United States. No internal insect parasites have been recorded 

 heretofore, and none was observed during the season of 1921. In 

 1922, however, a few native parasites of native insects were reared 

 from the bean beetle. 



Phorocera claripennis Macq. (PL XI, A) was common during July 

 and early August, and a considerable number were reared from egg 

 to adult in cages on third and fourth instar larvae of the bean beetle 

 during that period, but the species gradually became scarce and 

 disappeared from the field by September 1. The female fly deposits 

 distinct white eggs on the larva. (PL XI, i?.) Only one larva of the 

 parasite completes its development in the host. This species, although 

 the most common native parasite during 1922, did not become abun- 

 dant enough at any time to effect any appreciable natural control. 

 It has many other hosts. 



The sarcophagid fly Helicobia Jielicis Towns. 6 was reared in two 

 instances from bean-beetle larvae. This general feeder is also rare. 



In 1921 Prof. H. F. Wickham collected a puparium of a parasitic 

 tachinid fly in the vicinity of Mexico City, Mexico. In 1922 E. G. 

 Smyth, later in the season, collected numbers of these puparia and 

 shipped them to Birmingham, Ala. The fly occurs very late in the 

 season, but is reported to parasitize 30 to 50 per cent of the larvae 

 of Epilachna corrupta in Mexico. It has been recently described by 

 Dr. J. M. Aldrich as Paradexodes epilachnae. 1 More than 300 were 

 successfully reared in the insectary at Birmingham on third and 

 fourth instar larvae of the bean beetle, and a few were liberated. 

 A considerable number of puparia, also, were held in hibernation. 

 Emergence continued during mild weather in the winter, when the 



6 Determined by Dr. J. M. Aldrich, of the U. S. National Museum. 



7 Proceedings of the Entomological Society of Washington, vol. 25, No. 4, April, 1923, pp. 95-96. 



I 



