18 



ditch banks and roadsides; burning oft' in the fall of all trash on 

 stubble field — both corn and cane ground ; thorough cleaning of cane 

 before planting; running no second or third year stubble, and offbar- 

 ring stubble-cane as late in the spring as the weather will allow. 



Hand-picking of the beetles in the spring was quite successfully 

 employed by one planter. Children were paid small sums to follow 

 the " hoe gangs " and plows and pick up the beetles turned out. 



While further studies on the life history and habits of this insect 

 are necessar}^ and desirable, there are some points in its^ con- 

 trol which will readily be evident. One of the most important of 

 these is the disturbing of the grubs in the ground after freezing 

 weather sets in. Rather deep fall plowing Avill turn them out and 

 kill many, and if this is followed by a heavy harrow many more will 

 be destroyed. Planters in almost all the districts visited have stated 

 that this would also be of advantage to the soil. 



REPORT ON A MEXICAN COTTON PEST, THE " CONCHUELA." 



{PentatoiiHi ligata Say.) 



By A. W. Morrill. 



INTRODUCTION. 



A report reached the Bureau of Entomology in March, 1904:, to the 

 effect that a considerable falling off in the cotton crop for the season 

 of 1903, on a large plantation in the Laguna district of Mexico, was 

 believed to be due to the work of an insect. It was desired that the 

 matter be investigated by this Bureau, owing to the possibility of 

 obtaining information of value in connection with the study of cotton 

 pests in the United States. The writer was consequently detailed 

 to visit the plantation, the. headquarters of ^vhich are at Tlahualilo, 

 State of Durango, Mexico, and to ascertain if an insect was concerned 

 in the reduction of the yield of cotton for the previous season. 



At this plantation can be seen probably the most extensive con- 

 tinuous cotton fields in the world, covering from 25.000 to 30,000 acres 

 of land very nearly level, and comprising a portion of an old lake 

 bed, with fine alluvial soil, the great fertility^ of which would be 

 almost entirely unavailable but for Avater Avhich comes through irri- 

 gation ditches from the Nazas River, some 40 miles distant. Sur- 

 rounding the man}^ thousand acres of cultivated lands is a desert, the 

 principal vegetation of which consists of scattered mesquite trees. 

 At the time of the Avriter's first visit (March T to 10) there was 

 absolutely no green vegetation on the estate, except a few cactus 

 plants in the outlying uncultivated portions, thousands of poplar 

 trees growing along the banks of the irrigation canals, and a few 

 ornamental trees and shrubs growing about the offices and living 

 quarters of the managers. 



