172 C. B. WILLIAMS. 



The following are, I believe, the chief reasons why up to the present the froghopper 

 has done so little damage in Demerara as compared with Trinidad. 



(1) The conditions of climate and cultivation in Demerara favour a, continual 

 regular existence of the froghopper and its parasites throughout the year. The 

 absence of any long dry season together with the low level of the land makes the fields 

 always quite damp in some spots at least. This is particularly noticeable in the 

 narrow drains which occur at intervals of about six yards throughout the canes 

 and which have, even in the driest season, an edging of green succulent grass. 

 Between these drains the earth is banked up into high ridges on which the cane is 

 planted ; and these ridges are frequently too dry to attract the froghoppers from 

 the moist drains. As a result the froghoppers may be very abundant in the drains, 

 while the canes, except perhaps those bordering on the drains, are untouched. 



(2) The lesson learnt by the planters of Demerara from the invasion of the large 

 moth borer (Caslnia licus) has resulted in each estate having an organised insect gang 

 always at work, and as, in addition, they know from the unfortunate experience 

 of Trinidad that froghoppers are capable of serious harm, the slightest trace of them 

 in a field is reported and extremely energetic measures taken for their extermination. 

 In this way more money is expended in destroying them than the actual damage 

 caused, but the expenditure is more than justified as an insurance policy. 



(3) One of the most effective ways of dealing with the froghopper outbreaks in 

 Demerara is the flooding of the fields ; a control measure quite impossible in Trinidad. 



(4) The mongoose is still comparatively scarce. 



(5) Although on some estates quite a large proportion of the canes are burnt before 

 cutting, on account of the scarcity of labour, yet cutting is not confined to one season, 

 as in Trinidad, and there are always standing canes forming shelters. In addition, 

 burning, where practised, is always done at night when the ground is wet with 

 dew, or on moist days ; as a result it is not severe, the trash on the ground and the 

 grass in the drains remain, and the eggs and their parasites survive. 



(6) There is, in comparison with Trinidad, very little uncultivated land to serve 

 as a source of infestation. 



The list of enemies of the froghopper in Demerara is practically the same as in 

 Trinidad, and with the exception of the green muscardine fungus, there is little 

 that could be introduced. Any new parasite obtained for Trinidad should however 

 be useful also in Demerara. 



In addition to Tomaspis flavilatera, several other species of the genus Tomaspis 

 were found in British Guiana. As in most cases the identity of these is not yet settled, 

 particulars are reserved for a later date. 



References. 



H. W. B. Mooee. General Report on Insect Pests for the year 1911 to Messrs. 

 Curtis Campbell & Co. and Messrs. Booker Bros. Mc.Connell & Co., Georgetown, 

 Demerara (1912) p. 



Ditto for 1913 (1914) p. 15. 



Ditto for 1914 (1915) p. 15. 



Ditto for 1915 (1916) p. 7. 



Ditto for 1916 (1917) p. 9. 



