56 TBINIDAD AND TOBAGO BULLETIN. [XIX. ^\ 



In the field the two sexes appear to be in almost equal proportions. 

 A short account of the anatomy of the insect is given, based chiefly 

 on the work of Kershaw. 



During the heat of 'the day the insects remain hidden at the base of 

 the uijper leaves of the canes. In the late afternoon and evening 

 (earlier on cloudy days and later on bright days) they come up on to the 

 leaves and start feeding. The males begin to fly at about dusk. Light 

 traps examined every hour indicate that the greatest activity is from 

 dusk to 10 p.m. In the early morning they gradually return to their 

 hiding places in the axils of the leaves. 



From 40-100 eggs are laid by each female, either in the dead pai-tly 

 decaying leaf sheaths near tlie ground or in the soil itself. 



The egg is about one-thirtieth of an incli long, pale yellow in colour 

 and pointed at each end. As it develops a black longitudinal streak 

 appears at the head end. The egg stage lasts from two weeks to over 

 six months according to the conditions of moisture. Many eggs from 

 the second and third brood, however, do not appear to hatch until after 

 the following dry season. 



There are four nymph stages during which the insect increases in 

 size and the wings are developed. 



The nymphs suck the sap from the roots of the cane at and below 

 the surface of the ground. They protect themselves with a white 

 froth, which consists of the excretion of the alimentary canal in 

 which air bubbles are formed by an arrangement of the breathing 

 system. This froth is of considerable protection to the nymph from 

 extremes of drought and moisture and also from various predaceous ants 

 and other insects which arc often abundant in the cane fields. 



The froghopper feeds on sugar-cane, on almost all species of grass 

 (Gramineae) and on some grass-like plants of the related order 

 Cyperaceae. It has been reported damaging hill-rice, corn and pastures, 

 but has never done any serious injury to them in Trinidad. 



The nymph stages occupy five to seven weeks and the adult may live 

 as long as a month. The complete cycle under normal wet season 

 conditions takes slightly under two months. 



The first flight of adults is at the end of June or during July, about 

 seven weeks from the date of the first rains. The second brood is about 

 two months later, usually in September, and the third may appear after 

 a similar interval. Very occasionally a fourth brood appears about 

 December. The later broods are usually less distinct in their limits 

 than the earlier. During the dry season nearly all the froghoppers are 

 in the egg stage, but occasional unexplained records are known of adults 

 persisting through the dry season. 



Four other froghoppers of the genus Tomasjns are known in Trinidad. 

 T. rubra feeds on the Christmas Bush {Eupatormm). T. imhescens 

 feeds on grass, chiefly in moist spots along river banks, and is an 

 alternative host of some of the parasites of the sugar-cane frog- 

 hopper. T. O'lpiiiji also feeds on grass but is very rare and local. An 

 unidentified species is known only from two nymphs found on a creeper 

 on a forest tree in the mountains. There are also species of the genus 

 Clastoptera on Cas;uarina and Hibiscus, and Ccphisiis sp. feeding 

 possibly on Immortelle. 



