168 C. B. WILLIAMS. 



eggs collected at Plantation Ogle, East Coast, and one specimen was obtained by 

 sweeping the grass in the same locality. 



(2) Haplothrips sp. In one of my small breeding tubes containing only froghopper 

 eggs in dry trash I found a larva of a thrips which, under these artificial conditions, 

 was sucking the contents of the eggs. The larva was bred out and the adult proved 

 to be a species of the genus Haplothrips, a very abundant and widely distributed 

 genus of thrips, members of which have been previously reported to be occasionally 

 carnivorous ;* as a general rule, however, they are vegetarians. No effort was made 

 to introduce this insect into Trinidad, as several species of the genus are already 

 quite abundant there and it is questionable if they are of any serious value under 

 field conditions. 



Parasite of the Nymph. 



(3) The Syrphid Fly (Salpingogaster nigra). This was first recorded from British: 

 Guiana by Quelch in 1914. During my visit in May and June it was not seen, but 

 by the middle of August the maggots were quite common at Plantation Ogle, and a 

 few were seen at Cane Grove and Non Pareil, all localities on the East Coast. By 

 the middle of September there was a Syrphid maggot on nearly every cane stool 

 in that part of Plantation Ogle where the froghoppers were abundant. 



Parasites of the Adult. 



With the exception of the Green Muscardine fungus no true parasite of the adult 

 froghopper was found, but a number of predatory insects and lizards were observed 

 to feed on froghoppers to a greater or less extent. 



(4) The Green Muscardine Fungus (Metarrhizium anisopliae). In the course of 

 over two months spent in this district only a single adidt froghopper infested with 

 this fungus was foimd. This was on the 14th August 1916 at Plantation Ogle. No 

 infected nymphs were observed. This was entirely unexpected, when compared 

 with its relative abundance in Trinidad, and when one considers the moist conditions 

 in the cane-fields, which seemed extremely favourable for its propagation. In the 

 event of further trouble with this froghopper in Demarara, cultures should be obtained 

 from Trinidad and an attempt made to get it well established. It could not fail 

 to be of some value, as among its known hosts are included the smaller sugar-cane 

 borers (Diatraea spp.). 



(5) Dragonflies. Owing to the number of small drains with which the cane-fields 

 of Demerera are intersected, dragonflies are extremely abundant. One large green 

 specimen when captured readily took a froghopper adult, and as the dragonflies are 

 continually resting on and hawking above the short grass on which the froghoppers 

 are abundant, there is little doubt that they feed on them in the wild state. 



(6) Attid Spiders of several species were common and several times were seen 

 in the act of feeding on froghoppers. 



(7) Two species of predatory ants were observed carrying away adult froghoppers, 

 but the froth of the nymphs seems to render them immune from attack. On more 

 than one occasion hunting ants invaded my bench and killed all adult froghoppers 



* In Panama in 1917 I found another species of the same genus feeding on froghopper 

 eggs under similar conditions. 



