SECTION X. — -METHODS OF CONTROL 11.9' 



If this is done it must be i-ecognised that the method is under the 

 circumstances loncj and uncertain, and success is not even assured by 

 the arrival of the new parasite in Trinidad. 



From the experience gained in eighteen months spent in searching 

 for parasites in Central America two important notes can be added. 



(1.) The wide distribution of the common froghopper parasites in 

 Central America indicates that time will only be wasted searching for 

 new ones in this area and it is probable that the most rapid i-esults 

 would be obtained by going far afield. I should be inclined to recom- 

 mend the African continent, where numerous froghoppers of genera 

 allied to Tomasfis are known to exist. 



(2.) Such a search for pai'asites in new countries cannot be carried 

 out b}' one entomologist working alone and unaided. At least two men 

 and better still, three should be employed. The work will be more ,' 

 rapidly completed and more experience will prevent errors. To send j 

 one man is merely to gamble with the money expended, as the whole 

 investigation may be wasted if he is taken ill. 



In the section dealing with the natural enemies of the froghopper 

 some indications are given of the types oi parasite^ that might be 

 expected. 



Egg parasites are most likely to produce good results, especially if 

 capable of continuing their activities in dry weather, as the froghopper 

 is in the egg stage for the greater part of the year. 



Parasites of the nymph might include species of Drosophila ^at 

 present only known as parasitic on froghoppers of the genus Clast'iptera 

 {see p. 64). 



In Europe the nymphs of froghoppers of the genus Aphrophora are 

 taken from their froth and stored up by the wasp Gori/tes viistaceus 

 (Cambridge Natural History, Insects Vol. II. p. 9;3). No wasps have 

 yet been found storing froghoppers in Central America, but it is possible 

 that elsewhere others await discovery. 



Finally there are several other known species of the genus Salplngo- 

 gaster (which includes the Syrphid fly) and these are almost certainly 

 parasitic on froghoppers. 



Salpingogaster costalis Walk, S. minor, Aust. and S. virgata, Aust. 

 are known from Brazil. S. cotlmrnata, Big. S. limhipeimis Williston, 

 and S. nova, Gig-Tos, from Mexico. S. macula, Schin. from Chile. S. \ 

 nigriventris. Big. from Ui'uguay and S. pygophora Schin. from Brazil 

 and Panama (Kertesz Cat. Dipt. VII 1910 p. 168). S. pggopho}a \ms 

 also been reported from Cuba (Hine, Ohio Nat. XIV 1914 p. oo6). 



