384 Mr. H. Ling Roth's observations on 



The variation in colour, which is not capable of measure- 

 ment, is also very well marked. The original specimen, 

 of which all the subsequent progeny formed the material 

 on which my observations are based, was a not very dark 

 green. The offspring have exhibited all variations of 

 colour from a very pale green to a speckled fawn colour. 

 As a discontinuous variation there appeared at intervals 

 a few very dark speckled brown, almost black; three of 

 these were isolated and the 1237 eggs dropped by them 

 were kept separate. The accommodation at my disposal 

 was only sufficient to rear to the adult state some 475 of the 

 nymphs which hatched from these eggs. Of this number 

 only eight were of the very dark colour of the parents, the 

 remainder being various shades of green and fawn. The 

 hereditary tendency to transmit the dark colour, although 

 certainly present, is evidently weak. 



The insects forming the subject of these observations 

 have been reared under as uniform conditions as it. was pos- 

 sible to get, so that the effect of environment is eliminated 

 as a possible factor in the variation observed. 



The amount of variation as brought out in the table is 

 considerable; whether it is greater or less than in the 

 sexually produced forms of the same insect, if any, can only 

 be established when a similar series of observations on the 

 latter have been carried out. 



Summary of Observations. 



The observations were made under a regulated tem- 

 perature varying from 56° to 64° F. (13° to 18° C). 



The insects are of a lethargic disposition, feign death 

 when disturbed, and support themselves by their claws 

 assisted by their pads, which do not act by surface tension. 



In colour they vary from a light fawn to a dark green ; 

 very dark brown almost black is rare. During life the 

 colour barely changes. 



Incubation in the boxes varied from 137 to 297 days, 

 equal to a range of 160 days; 52*7% of nymphs hatched 

 out in 141 to 160 days, and 32-3% in 161 to 190 days. 

 Placed on garden mould the hatching out commenced 

 16 days sooner, i. e. in 115 days, with a somewhat similar 

 average range. 



The insects were parthenogenetic, and only one specimen, 

 obviously an infirm female, failed to produce eggs. One 



