THE SWEET-POTATO LEAF-FOLDER. 9 



insectary, since the temperature of the insectary is higher than the 

 outdoor temperature. In outdoor cages moths began to issue on 

 August 24 and August 26, 28 and 29 days after the eggs had been 

 deposited. 



It appears that during the summer months the life cycle requires 

 about five weeks in the field at Baton Rouge. Early in September, 

 moths, pupa?, and larvae in all stages of development were found on 

 sweet-potato vines. There are probably four, and possibly five, gen- 

 erations during the season in the latitude of Baton Rouge. 



NATURAL ENEMIES. 



A tachina fly (Exorista pyste Walk.) and an ichneumon fly which 

 Mr. A. B. Gahan, of the Bureau of Entomology, has pronounced to 

 be a new species of the genus Bassus, have been reared from collec- 

 tions of larvse made in the field at Baton Rouge, indicating that they 

 are parasites of the sweet-potato leaf-folder. Adults of the spined 

 soldier bug (Podisus maculiventris Say) have been observed with 

 larvae impaled on their beaks. 



Mr. High observed a predacious enemy of the larva in the "jack- 

 daw," or boat-tailed grackle {Megaquiscalus major maerourus Swain- 

 son). The following notes are from his records. 



" This bird winters in southern Texas by millions and feeds on a number of 

 insects that attack truck crops and particularly on larvse. -* * * observed 

 it first feeding on the cabbage looper (Autographa brassicw Riley) in 1913, 

 two days after cabbage had been sprayed with an arsenical. 



"Some species of larva? after being poisoned have a habit of crawling to the 

 top leaves of the plant upon which they are feeding before dying, and here 

 they fall easy prey to the grackle. The poison apparently does not seriously 

 affect the birds, since none have been found dead in the vicinity of sprayed 

 crops.'" 



THE SWEET-POTATO LEAF-FOLDER IN SOUTHERN TEXAS. 1 



The sweet-potato leaf -folder (Pilocrocis tripunctata Fab.) was 

 first observed by the writer in southern Texas September 17, 1916, 

 when larvae were found sparingly on a plat of sweet potato at 

 Brownsville, Tex. On September 29 the larvse were observed at 

 work in another field near Brownsville, and by this time were more 

 numerous in the plat where first they were found. At this time a 

 sudden change in the weather accompanied by hard showers somewhat 

 reduced their numbers. 



By the middle of October the caterpillars had become so abun- 

 dant that it was found advisable to spray immediately. Later a 



1 Reported by M. M. High. Entomological Assistant. Bureau of Entomology, United 

 States Department of Agriculture. 



