09 



NOTE ON ANTHOCHARIS. 

 By T. a. Chapman, M.D., F.E.S. 



Having obtained a few pup<e of AuthocJiaris belemia, aud so 

 had the opportunity of observing the butterfly aHve at leisure, I 

 observed one little fact that is probably well known, but may be 

 new to others as it was to me, and is interesting in connection 

 with the protective colouration in the genus. We are all familiar 

 with the green aud white spotting of the under side of A. car- 

 damines and its nearest allies, and how the insect at rest 

 assimilates closely to white flowers over green foliage both in 

 general and detailed effect. No doubt the flowers contemplated 

 are such white GruciferiB as Erysimum aUiaria (garlic mustard), 

 the most frequent food-plant of the species with us, but not at 

 all out of harmony with many Umbelliferae and other flowers. 



The colours are the same in belemia, but they are here 

 disposed in irregular stripes crossing the wings at an angle, 

 irregular both as to width and intersection, but still distinct 

 transverse stripes instead of spots. Now my one little fact is, as 

 to the resting attitude of the Ijutterfly, which sits with the wings 

 closed in the usual way, the head close down to the surface in 

 which the butterfly is seated, and the antennae porrected so as 

 to lie close together and appressed to the resting surface. The 

 abdomen and the inner margin of the hind wings between which 

 it is hidden are raised from the surface at a considerable angle 

 (30^-40^), with the result that the stripes of green and white are 

 exactly parallel in general direction with that surface. Supposing 

 this to be a blade of grass or a petiole of a flower, amongst others 

 all substantially parallel, then the green stripes would accord 

 with these. Someone who has seen the butterfly at home may 

 be able to tell us with what the white stripes agree. Probably 

 the white really agrees with those portions of foliage that strongly 

 reflect light and look white and glistening, the green portions 

 according with the general tone. I should imagine, however, 

 that this insect rests amongst foliage of a spiked or grassy 

 character and not close to the flowers, as in the case of car- 

 damincs, belia, daplidice, &c. 



In these there is little doubt that the white does refer to the 

 flowers, when we see in eupJienoldes, a species that is attached, 

 I fancy exclusively, to Biscatella, with yellow flowers, that the 

 surface that is white in the other species is here yellow. 



We can hardly help comparing this case with that of the 

 tiger and the leopard, where striping and spotting are co-related 

 with hiding in grassy jungle and leafy forest, and with the 

 parallel difference in marking between paplda, &c. — and adippc, 

 &c., which has not, so far as I know, been attributed to any 

 differences as to their preference in hiding-places. 



Betula, lleigate : February, 1900. 



ENTOM. — MARCH, 1900. H 



