A FROGHOPPER ON SUGAR-CANE IN BRITISH GUIANA. 165 



same year Mr. Quelch bred out the parasitic Syrphid fly, Salpingogaster nigra, from 

 maggots found at Cane Grove. 



In 1915, froghoppers were abundant in July and August at Plantation Ogle ; 

 386,222 nymphs were collected by hand and destroyed. " This is the first occasion 

 on which it has assumed alarming proportions " (Moore, Report for 1915, p. 7). 

 The fields were also flooded for some days and the nymphs which crawled up the 

 stems were shaken off into the water ; in this way many thousands were destroyed. 

 The Syrphid fly was also found in this locality for the first time this year. 



My first observations in the field were at the end of May and the beginning of June 

 1916, when Tomaspis flavilatera was found occasionally on several estates, but was 

 nowhere common. Females in captivity readily laid eggs on dead trash (see below). 

 The nymphs and adults were chiefly in the short succulent grass along the narrow 

 drainage trenches running through the canes, and the adults could be readily caught 

 by sweeping along these with a strong net. 



After two months absence I returned to the district again in August and September, 

 when the insects were much more numerous, but were still causing practically no 

 damage. One estate (Plantation Ogle) had already started collecting the nymphs 

 by hand. 



During my two visits I found the froghopper generally distributed along the East 

 Coast and in small numbers on a plantation just west of the Essequibo River. 

 Although the West Coast was visited on several occasions, none were seen there, and 

 I understood that neither Mr. Bodkin nor Mr. Moore have any record from this Coast. 

 In spite of this I think there is no doubt that it will be found to occur there in small 

 numbers. 



The Egg. 



Eggs were first obtained in captivity on the 3rd June 1916. They were laid in 

 the dead moist leaf-sheaths at the base of the grass stems near the ground, in a 

 position quite similar to that adopted by T. saccharina in Trinidad. In cane and 

 in grasses with thick leaves the egg is inserted between the two surface layers with 

 the anterior end very slightly projecting. In grasses with thin leaves the egg may 

 be passed through one or more leaves and embedded in a deeper layer. In one 

 case in which a thin dead leaf was covering some living tissue an egg was inserted 

 through the dead layer into the green tissue beneath. This was the only case in 

 which an egg was found in green tissue. 



The eggs are pale yellow in colour when first laid. They are 0"88 mm. long and 

 0*29 mm. broad ; spindle-shaped, slightly more pointed at the anterior than at the 

 posterior end. After some days a dark longitudinal streak (the hatching lid) appears 

 at the anterior end, quite similar to that found in Tomaspis saccharina. 



The Nymph. 



Stage I. Total length, 1-2 "5 mm. Pale yellowish-brown, with a slight red-brown 

 mark on either side of the abdomen. (The young larva of Tomaspis pubescens, 

 the black froghopper, which is the only other grass-feeding species found in this 

 district, can be distinguished at this stage by its orange-red colour ; although 

 -occasionally occurring on grass, it was not found on sugar-cane.) No traces of 



