April, '11] URICH: SUGAR CANE INSECTS 225 



changes have taken place, better varieties of canes are grown and the 

 methods of cultivation leave nothing to be desired. 



Besides the pests of old standing such as Diatrcea saccharalis, 

 Sphenophorus sericeus and Rhynchophorus palmarum, two insects, 

 Tomaspis postica and Castnia licus have been more injurious than all 

 the others put together. Tomaspis postica appears to have existed on 

 cane in this island for a long time, but it was only in 1908 that these 

 Cercopids were recognized as being the authors of a cane blight that 

 caused considerable loss from time to time. From its original food 

 plant, grass (several species) T. postica adapted itself so well to sugar 

 cane that today a hard fight is taking place to eradicate it from sugar 

 cane plantations. The life history of this insect has been fully worked 

 out and some of the stages appear to be more vulnerable than others, 

 but one of the chief difficulties in combating not only this insect, but 

 many other insect pests in the tropics, is the continual succession of 

 broods and continuous generation which take place. Only abnormal 

 conditions of weather seem to exercise a slight check as far as T. pos- 

 tica is concerned, extremes of dry or wet weather keeping it down. 



Contrary to the habits of some members of the Homoptera T. 

 postica inserts its eggs by means of the ovipositor into the tissue of 

 withering cane or grass sheaths instead of choosing green and growing 

 tissues. The eggs are deposited singly, and take, in favorable weather, 

 from twelve to twenty days to hatch. In very dry weather eggs do 

 not hatch immediately and this would appear to be the only resting 

 or aestivating stage of the insect. The young nymph makes its way 

 to the ground, attaches itself to the nearest cane or grass root and 

 surrounds itself with the spittle characteristic of the Cercopidse. 

 The nymphal stage lasts from thirty-two to forty-two days and during 

 this time skins are shed four times, the cast skins remaining in the 

 spittle mass. 



When the final moult is about to take place, the nymph ascends afoot 

 or two on a grass stalk or cane and in a kind of hollowed-out chamber 

 in the froth undergoes the final moult. The newly issued adult remains 

 in the chamber until quite strong and fully colored, a process requiring 

 several hours. The proportion of males and females in the fields varies 

 according to season, but on an average 51 per cent of the total number 

 are males. Each female is capable of laying thirty to forty eggs. 

 T. postica in its nymphal stage appears to be so well protected that no 

 natural insect enemies have been observed, the only natural control that 

 has been found to be of some use is a parasitical fungus, which attacks 

 both adults and nymphs, but mostly the former. Mr. J. B. Rorer has 

 identified this fungus as M etarrhizium anisoplice Metschnikoff. Ex- 

 periments with the fungus conducted on a small scale have given 



