58 FROtillOPPEll BLIGHT OJ' SUGAR-CANE. 



of darkness with a gradual and regular reduction throughout the night, 

 and further that over half the total were caught in the first three hours. 



In the early morning the reverse process takes place to that in the 

 evening and by 7.30 a.m. to 9 a.m. according to the brightness of the 

 day, all the adults have returned to their hiding places in the axils of 

 the leaves. 



Feeding takes place at night and the amount of sap sucked out by 

 one insect is extremely large. Dm-ing the whole time of feeding drops 

 of liquid excreta are ejected from the anus at a rapid rate. According 

 to McLeod (1908 p. 554) a drop of excreta is produced every 12-13 

 seconds. '' A single insect under observation extracted and voided 

 ^ drachm of clear liquid in one hour." With fifty froghoppers per stool 

 each sucking tor eight hours during the night about one and a quarter 

 pints of sap would be removed from each stool during the night. This 

 drain would last from two to four weeks in bad attacks. 



Kershaw fl913 G. p. 100) notes that the excretion tested by two 

 different methods showed no trace of sugar while sap extracted directly 

 from the leaves was found to contain plenty. The absence of sugar in the 

 excretion probably accounts foi the fact tliat no "black blight" fungus 

 growth appears on the infected plants as is the case with tlie cane-fiy 

 (Deljihax). 



At this point it might be mentioned that, in company with a planter, 

 I tasted an adult froghopper, and we agreed that the taste resembled 

 that of grass and was not unpleasant. ^ 



Pairing appears to take place at all times of the day and night. Urich 

 considers (1918 C. p. 17) that the female pairs shortly after emergence 

 and both Urich and Kershaw state that the males probably only pair 

 once. More evidence is required on this point as, should it prove to be 

 true, the use of light traps in the fields might be of greater consequence 

 even if only mules are destroyed thereby. 



Egg laying takes place usuall_\ at night. In captivity the eggs may 

 be laid in any material that can be pierced by the ovi]:)ositor of the 

 female, as for example in damp blotting paper, but in the field the eggs 

 are laid in two definite situations : (1) in the dead partly decaying 

 moist leaf sheaths near the ground, or (2) in tlie ground itself. 



The eggs are laid two or three at a time at short intervals and a total 

 of from forty to one hundred can be laid b.v one female. Kershaw (1913 

 G. p. 95) from dissection considers that 120 is the maximum number 

 that can be laid and thar they are matured in three batches. 



THE EGG. 



Description. The egg is about 0*75 mm. long by about 0*25 mm. 

 wide (0'03 x O'Ol inches). Three times as long as wide and more pointed 

 at the anterior end than at the posterior. For the first few days it is 

 yellow in colour, but a dark longitudinal streak gradually develops at its 

 anterior end leading from the tip to about half the length of the egg and 

 broadest near the anterior end. This is the hatching lid which breaks 

 away from the rest of the shell and allows the 3'oung insect to emerge. 



Kershaw (1913 G. p. 96) has described in detail the internal structure 

 of the egg and the position of the "egg Ijurstei" which is used by the 

 young nymph to force up the hatching lid. 



Position. In the dead leaf sheaths of the cane and grass the eggs 

 are inserted head-end upwards and slightly projecting outward in a slit 

 made by the ovipositor of the female in tlie tissue between two vascular 

 bundles. The trash chosen by the female is nearly alwaj'S that moist 

 partly-decayed trash which is attached to the stem within a few inches 

 of the ground. Eggs are also laid in a similar manner in the earth round 

 the base of the stool. In British Guiana T. fiavilatera has been found 

 by Moore (1919 p. 9) to lay also in this situation, particularl3', he 

 believes, in the soft earth of worm casts. 



