SECTION VI.— NATURAL ENHMIKS OF TIIK FR,0(UIOI>['i;U. ()7 



Of the seventeen birds tliere recorded as feeding on the adult only 

 three have been proved to eat nymphs. These are : — 



ICTKRID.E. 



(1.) Trinidad Boat-tail {Qnisqualus luc/iibria.) 

 (2.) Golden Head {Agelaiuft ictcrocephalus.) 



MnIOTILTIDvE. 



(3.) Manicou Bird (GeoUih/pim aequinoctialis.) 



Other birds doubtless also take them occasionally, but the froth in 

 which the nymphs are enclosed must serve as a partial protection. 



The Boat-tails have a habit of following the ploughs and diggers in 

 the field, in the manner of crows in England, and obtain many nymphs 

 in this way. 



The Syrphid Fly. {Salpiiigogaster nigra, Schiner). * 



This fly, the maggot of whicJi is parasitic on the nymphs of the 

 froghoppers, was first noted by Gough in 1910 (1911 C. p. 18j and first 

 bred to the advilt stage by Urich (l'.ir2 D.) 



The adult fly (Fig. 11.) is about two-thirds of an inch (14-16 mm.) in 

 length and nearly one inch (20-22 mm.) across the open wings. Ic is 

 blackish brown in colour except for a narrow band behind the 

 thorax ,two spots on the side of the abdomen, and the bases of the tibiae 

 of the legs, which are yellow. The front border of each wing is suffused 

 with dark brown. 



The abdomen is long and joined to the thorax by a long stalk 

 (petiole) which gives the fly a close resemblance to some species of wasps. 



The inost complete record of the life history has been given by 

 Guppy (1913). According to his account, the egg is about "TSmm. long 

 elongated and shining white in colour. It is laid in the frotli. The egg. 

 stage lasts about two to two and a half days. 



The footless maggot which hatches out destroys the frog- 

 hopper nymph hy piercing its inti^gument and sucking out the contents. 

 This stage lasts about nine days. According to Guppj' one maggot 

 destroys about 30-40 froghopper nymphs during its development. 



Fig. 10. 



Fig, 10 — The .Syr[»lii(l Hy ; pu|)a. 



