APHIS BRASSIO^. 33 



birds ; thus, the usual prevaiKng green colour of 

 the parrot's plumage passes iuto the crimson colours 

 of the Molluccas and New Guinea species, &c. 



Recently the same investigator seems to deny in great 

 part the direct modifying action of solar heat and light, 

 or at any rate he points out that they are inadequate by 

 themselves to produce such colour modifications. He 

 rather would look to the superior activity and vitality 

 of the male as a cause for the often greater brilliance 

 of his hues, although, singularly, such increase of bril- 

 liance is often attended by a reduction of size in 

 reference to the female. 



The large increase of brilliancy of plumage amongst 

 many birds at the breeding season is patent to all, and 

 it has been suggested that some cptasi molecular change 

 might take place in the cases of both insects and birds 

 under the excitement of anger, jealousy, and sexual 

 pugnacity, which by some unknown process might be 

 perpetuated and intensified, by developmental or the 

 like causes, presumably for the benefit of the indi- 

 vidual. 



Such questions form tlie legitimate subject of scien- 

 tific inquiry, and he who adds to our accurate know- 

 ledge in such difficult paths of research earns the 

 hearty thanks of the Biologist.* 



Aphis beassic^, LIjiu. Plate XL VI, figs. 1 — 6. Linn., 

 Schr., Fabr., Kalt., Walk., Koch, Pass. 



Aphis raphanif Schr., Mosley. 

 „ floris-rapce, Curtis. 



Apterous viviparous female. 



Incli. Millimetres. 



Size of body 0-090X0-050 2-27xl-27. 



Length of antennae 0*060 1*54. 



cornicles 0-010 0-25. 



* Vide Mr. Wallace's Address to the Biological Section of the British 

 Association at Glasgow, 1876. 



VOL. II. 3 



