26 BULLETIN 1243, U. S. DEPARTMENT OF AGRICULTURE. 



will no doubt require many years for native enemies to become adapted 

 to it. No insect or other enemy has been observed to effect any 

 appreciable control in the western part of the United States. 



PREDACIOUS ENEMIES. 



The following predacious insect enemies have been observed to 

 prey on the Mexican bean beetle, Epilachna corrwpta, in the field, and 

 most of these have been observed in confinement. 



The common coccinellid beetle, Megilla maculata DeG., was very 

 abundant about Birmingham, Ala., during the summer of 1921. 

 This beneficial species fed, in both the larval and adult stages, on 

 the eggs of the bean beetle, and occasionally on young larvae. Many 

 egg masses were attacked and a few eggs of each destroyed. The 

 bean beetle was so abundant that less than 3 per cent of the eggs 

 were destroyed. During 1922 Megilla was not abundant, and very 

 few eggs were destroyed. 



The convergent lady-beetle Hippodamia convergens Guer., also eats 

 the eggs of the bean beetle, but sparingly. The adults of Coccinella 

 sanguinea L. and G. novemnotata Hbst. feed slightly on the eggs, the 

 latter species more generally on younger larvse. Adalia bipunctata 

 L. feeds slightly on the eggs and small larvae. 



A common soldier-bug, Stiretrus anchorage* Fab., destroys larvae, 

 pupae, and beetles. It is not common until late in the season, and 

 then is not sufficiently abundant to be of much value. This bug, 

 both in the last nymphal and in the adult stages, is at present the 

 most effective native enemy. 



Another pentatomid bug, Podisus maculiventris Say, feeds in both 

 nymphal and adult stages on larvae, pupae, and adults of the bean 

 beetle and is a more active feeder than Stiretrus. It is not generally 

 as numerous as Stiretrus, and is therefore less effective. Both of 

 these bugs can subsist for long periods on a bean beetle diet. 



The common wheel-bug, Arilus cristatus L., feeds on larvae, pupae, 

 and beetles, but is too rare to be effective. 



The ground beetles might be expected to prey on the bean beetle, 

 especially when the latter is so abundant as to destroy a field of beans 

 and the larvae crawl about in search of food. No beneficial effects 

 have been observed from this source, though three native species, 

 Harpalus caliginosus Fab., Scarites subterraneus Fab., and Calosoma 

 sayi Dej., eat larvae sparingly, and the latter two species attack 

 pupae and beetles in confinement. 



The tiger beetles Tetracha Carolina L., and T. virginica L., both 

 larvae and adults, feed voraciously in confinement on larvae, pupae, 

 and adults of the bean beetle and occur in infested fields. It is not 

 certain that they feed voluntarily on this insect in nature, and their 

 habits would not indicate that they are very important enemies. 

 They are not present in numbers in well-cultivated fields. 



The larvae and adults of the lace-wing flies Chrysopa ocuiata Say 

 and C. rujildbris Burm. feed on pupae of the bean beetle. They are 

 not numerous and are of little importance. 



In the fall of 1921 a number of instances of feeding by caterpillars 

 on pupae of the bean beetle were noted* In three instances the larvae 

 matured in confinement on a diet of bean-beetle pupae and developed 

 into normal moths, two of which were identified by Dr. F. H. Chitten- 

 den as Prodenia ornithogalli Guen., and the third as Laphygma 



