16 



molted, and was at this time only 3 mm. long. A majority of these 

 larvae would probably have left" the vines before the middle of August. 



From the observed fact that a bean vine if infested at all is usually 

 attacked in two to half a dozen places, it is patent that a moth deposits 

 several eggs on a vine before leaving it. In one instance two galls 

 appeared about three inches apart. 



As a rule only a single larva inhabits a gall, but one was found in 

 which two were domiciled, one nearly grown, appearing to be the 

 original habitant, and the other, less than half grown, an interloper. 



THE SPECIES PARTIALLY DOUBLE-BROODED. 



Two of the moths issued August 15 and these were all that were 

 obtained that month from our rearing jars. One other moth issued 

 September 7. Examination of the jars showed that they contained 

 cocoons and when one of these was cut open, September 12, it was 

 found to contain the larva. 



The same day the writer visited the infested locality, finding that 

 few larvae still remained in their galls. It was also noted, as we had 

 reason to expect, that a second generation had begun to attack the 

 plants. 



The second generation about the District of Columbia is a very small 

 one, the majority of the first generation wintering over, probably as 

 larvae, as several species of insects are known to do here. In short, 

 the species is only partially two-brooded, in this respect resembling 

 the squash-vine borer and certain chrysomelid beetles, which are not 

 fully double-brooded in this locality. 



Farther north, if the species extends toward the Transition zone, 

 which seems doubtful, there would be without doubt only a single 

 generation, and southward in the Lower Austral we may be equally 

 sure to have two well-defined generations each year. 



A larva obtained in the field September 11, and undoubtedly of the 

 second generation, required about a week longer to complete its growth 

 and was found spun up September 26. 



It is evident that the second generation is able to complete its develop- 

 ment before the crop is made. 



NATURAL ENEMIES. 



The first generation of this insect appeared to be absolutely free 

 from the attack of any natural enemies, either parasitic or predaceous, 

 none of the galls harboring any other insect than its original occupant. 

 In galls produced by the smaller generation a single parasitic pupa 

 was found in September. This transformed to adult on the 1th of 

 that month, and the specimen on being referred to Mr. Ashmead was 

 identified as Omjihale livida Ashm. , originally described from Florida. 



