450 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 6 



be feared so long as the collection is kept up, and even should Castnia 

 become abundant again, there would be no cause for alarm, as the 

 measures of control are well known and their effectiveness has been 

 demonstrated. 



When one enters a field where the cane is soon to be cut, his first 

 impression is of the enormous amount of cane that has been seriously 

 injured by Diatrcea. This primary injury by Diatroea is sufficiently 

 important in itself, but in addition there is the secondary infestation 

 by other insects that only enter cane that has been previously injured 

 by something else. . . . All stages of the weevil stalk borer, 

 Metamasius hemipterus Linn., are to be found in the greatest abun- 

 dance. If this pest were able to reproduce rapidh' and survive adverse 

 conditions, the injury it might produce would be very great, but 

 nowhere was it observed to cause nearly so much injury as Diatroea. 



Much cane is also injured by termites, or "wood ants" as they 

 are called by the planters. They never attack sound cane, but as 

 all the cane in Demerara is infested with Diatrcea, the termites have 

 no difficulty in finding a place of entrance to the interior of the stalk. 

 They hollow out the stalk so completely that only a thin shell remains, 

 which easily breaks through when grasped in the hand. The termites 

 use the cane stalks as a source of food and building material, and as 

 a living place. They also build many galleried nests, the individual 

 walls of which are thin as cardboard and break through readily, but 

 the nest will not break into large pieces even when subjected to rough 

 treatment. It is a common practice to carry these nests from the 

 field when the cane has been cut, and burn them on the towpaths 

 at the edge of the field. This control measure seems to be rjuite 

 effective, although the danger of gravid females dropping from the 

 nest while it is being carried across the field, is quite serious. The 

 nests undoubtedly should be carried in a bag or on a tray. 



The sugar-cane mealy bug, Pseudococcus calceolarics Mask, was 

 moderately abundant in most fields. As compared with the injury 

 caused by Diatrcea and Castnia, the mealy bug is not considered a 

 serious pe.st. Its numbers are kept in check somewhat by a predaceous 

 lady beetle, the name of which has not been determined. 



The final impression one carries away with him of the cane insect 

 problem in Demerara concerns chiefly the following points: 



(1) The enormous and wide-spread injury by the smaller moth 

 borer, which despite all control measures now being used against it 

 and the natural control by the various parasites, seems to be holding 

 its own and is most decidedly not less abundant than it was at any 

 time in the past. 



