262 



leaves occurs from dusk to early morning, when the adults retire to the 

 shelter of the axils of the leaves. From 40 to 100 eggs are laid by 

 each female, either in decaying leaf- sheaths near the ground or in the 

 soil. The egg-stage lasts from two weeks to over six months, according to 

 moisture conditions ; many eggs from the second and third generation 

 do not appear to hatch until after the following dry season. There are 

 four nymphal stages, lasting five to seven weeks, during which the insects 

 are protected by a white froth, while they suck the sap from the roots 

 at and below the ground surface. The complete life-cycle under normal 

 wet-season conditions takes rather less than two months. Other 

 food-plants are various Gramineae and some Cyperaceae ; hill-rice, 

 maize and pastures have also been attacked. The first generation of 

 adults appears in June or July, the second usually in September, and 

 the third about two months later. Very rarely a fourth generation 

 appears about December, the later generations overlapping somewhat. 

 Other species of froghopper that occur in Trinidad are : — T. rubra, 

 on Eupatorium ; T. pubescens, on grass in moist places, serving as an 

 alternate host of parasites of T. saccharina ; T. giippyi, feeding on 

 grass ; and an unidentified species found on a creeper in the mountains. 

 Clastoptera spp. feed on Casuarina and Hibiscus, and Cephisus sp. is 

 thought to feed on immortelle [Erythrina]. 



The natural enemies of the froghopper include the egg-parasite, 

 Oligosita giraulti, which requires about 30 days for its life-cycle and 

 breeds chiefly during the dry season, when the froghopper is inactive. 

 It is probably native to Trinidad, and will not increase much beyond 

 its present numbers. Other egg-parasites of less value are Para- 

 phelinus tomaspidis and Anagrtts sp. ; Haplothrips spp. and ants are 

 predators. The nymphs are eaten by a few birds, but their most 

 important enemy is a Syrphid fly {Salpingogaster nigra), which ovi- 

 posits in the froth, the resulting maggot, which hatches two days later, 

 destro3'ing the nymphs by piercing their skin and sucking out the body 

 juices. The life-cycle of this fly occupies about three weeks ; in the 

 moister localities it occurs throughout the year, but in cane fields it 

 is seldom seen before the second or third generation of frog hoppers. 

 A Nematode, about which very little is known, is occasionally found in 

 the body of the nymph or adult. 



There are many parasites and enemies of the adult froghopper, 

 including many birds, lizards, the grasshoppers, Xiphidium and 

 Pflugis, ants, Reduviids and Attid spiders. The green muscardine 

 fungus {M etarrhizium anisopliae) is probably the most important 

 natural check, generally appearing with the later generations, if 

 conditions are favourable for it. Attempts to disseminate this fungus 

 have as yet given inconclusive results, but the subject is worth further 

 investigation. Another fungus, a species of Enipusa, kills many 

 adults, but never appears before October, and is much rarer than 

 M. anisopliae. 



An account is given of the cane-root fungi of the Marasmius and 

 Odontia- Himantia types, and the effects of weather conditions 

 {R. A.E.,A,Vn\., 131], type of soil, drainage and manuring, the age 

 •of the cane, rotation, tillage and varieties of cane used [R.A.E., A, 

 vii, 531] are discussed. The relative importance of adult and n^onph 

 froghoppers and of root disease is reviewed. The froghopper is con- 

 sidered the most important cause of blight because of its constant 

 presence in affected areas, the streaking of the leaves, the occurrence 



