152 . Mr. E. Ernest Green's Remarks on 



With regard To clause five, T hold the opinion that the 

 resemblance is superficial only. In his tabulated differ- 

 ences between viride and psidii the author pays no atten- 

 tion to dimensions, and there is nothing to indicate whether 

 his figures are drawn to scale or not. Though the over-all 

 measurements of the two insects fall within the same 

 range of variation, this is by no means the case with respect 

 to the size of the various organs and the proportionate 

 lengths of the joints of the limbs. In spite of the fact 

 that the two insects are of approximately the same size, 

 it will be seen (vide accompanying text figures) that all 

 the organs of viride are very much smaller than the corre- 

 sponding structures of psidii. Taking these in order, we 

 find that the length of the antenna of typical viride is to 

 that of psidii in the proportion of -V) to 97. A still more 

 striking contrast is seen in a comparison of the legs of the 

 two species, which are in the proportion of ft to 15 (femur 

 11 to 28, tibia 7 to 22. tarsus b to 11). The proportions 

 of other organs show corresponding differences : anal 

 operculum (length) as 8 to 11, (breadth) as 18 to 25; 

 orifice of posterior spiracle, as 9 to 17; marginal hairs, as 

 2 to 13. The relative proportions of the joints of indi- 

 vidual limbs also show strong points of difference : in 

 viride. the femur is to the tibio-tarsal member as 11 to 12, 

 and the tibia is to the tarsus as 7 to 5; while, in psidii, 

 the same members are in the proportion of 28 to 33 and 

 22 to 11 respectively. Thus we find that, while in viride 

 the tarsus and tibia are approximately equal in length, 

 in psidii the tibia is twice as long as the tarsus. The 

 relative lengths of these two joints are usually accepted as 

 useful specific characters. 



The fact that a reduction in the number of antennal 

 joints has been observed in South Indian specimens of 

 both viride and psidii does not. in my opinion, provide an 

 argument in favour of the transmutation of the two species ; 

 but suggests, rather, that a similar environment has 

 induced a tendency to variation in the same direction. 



The author remark's that "the main distinction on 

 which Green appears to rely is that psidii secretes meal 

 and viride docs not." I am sorry if any such opinion is 

 to he gathered from my descriptions of the two species. 

 I maintain that 1 he similarity is purely superficial, and that 

 an examination of the microscopic characters would make 

 it impossible to confuse the two insects. 



