122 ENTOMOLOGICAL NEWS [May, '2O 



been observed by the writer attacking cotton. A report of 

 severe damage from its attack reached the Station from the 

 Haltillo district during July, 1919, but specimens accompany- 

 ing the letter proved to be those of the leaf caterpillar, Ala- 

 bama argillacea Hiibn., the two species having been confused. 

 Even as a pest of green ear-corn, the boll-worm is considerably 

 less important on the Island than the southern grass-worm, 

 Laphygma frugiperda S. & A., which in several islands of the 

 West Indies is known locally as the corn ear-worm. 



The cotton leaf caterpillar often becomes locally a serious 

 menace to cotton raising. To combat it by means of arseni- 

 cals, by the dusting method, as is done in the Southern States, 

 is too expensive for the average cotton grower of the Island, 

 who is usually so lacking in funds as to be unable to buy even 

 his seed, which must be furnished by contract. He is there- 

 fore advised to use a much cheaper but equally effective me- 

 thod of control, namely, the cutting down and destroying of 

 the moth's wild food plants between cotton crops. Principal 

 of these are two weeds, Urena lobata and Malachra rotundi- 

 folia, both Malvaceous, the former much the more abundant, 

 and the more noxious from its habit of attracting large num- 

 bers of the fire-ant, Solenopsis geminata Fabr., because of the 

 three small honey-ducts on the underside of each leaf. It is 

 unfortunate that this plant is considered highly medicinal by 

 the natives, and with difficulty are they persuaded to cut it 

 down. The weed grows in considerable beds when permitted 

 and the writer has collected as many as 52 larvae from four 

 plants (on July 16, 1916), showing how the weed may facili- 

 tate the moth's multiplication. In many cotton sections of 

 the States this moth breeds continuously upon cotton, hiber- 

 nating over winter at end of the cotton season, and flying 

 forth in spring in time to invade the new crop. There it needs 

 no alternate host plant. But in Porto Rico conditions are 

 different, there being a long period between cotton crops dur- 

 ing which the moth cannot hibernate, so must breed on other 

 plants. Urena lobata not only tides over this gap, but allows 

 the moths to greatly multiply in numbers between cotton 

 crops, it being in many regards a more favorable food plant 

 for the larvae than cotton. 



