HA RD WICKE'S SCIENCE- G OSSIP. 



i7 



The sixth and last part of this magnificent work is 

 now published ; and we shall not be surprised now to 

 see it going up in price. The plates of the present 

 part are of equal artistic merit to the rest of the series. 

 We heartily congratulate the authors upon the high 

 success of their work, and the way in which it has 

 been received by the scientific public. 



Entomology and Geology. — At the last meeting 

 of the Entomological Society of London, Mr. Howard 

 Vaughan exhibited a long series of Gnofhos abscurata, 

 comprising specimens from various parts of Ireland, 

 North Wales, Yorkshire, Berwick- on - Tweed, the 

 New Forest, Folkestone, Lewes, and the Surrey 

 Hills. The object of the exhibition was to show 

 the variation of the species in connection with the 

 geological formations of the various localities from 

 which the specimens were obtained. 



The Hessian Fly. — To xhe same meeting, Miss 

 E. A. Ormerod communicated a paper " On the 

 occurrence of the Hessian Fly {Cccidomyia dcstntctor) 

 in Great Britain." It appears that there could be no 

 longer any doubt as to the occurrence of the insect in 

 this country, specimens obtained in Hertfordshire 

 having been submitted to, and identified by, Pro- 

 fessor Westwood, and by Mr. W. Saunders, of 

 London, Ontario. Professor Westwood , said the 

 specimens agreed exactly with Austrian specimens 

 in his possession, sent to him some years ago by 

 Mons. Lefebre, who had received them from the 

 late Dr. Hammerschmidt, of Vienna. 



ANIMAL PSYCHOLOGY. 



About Crows. — Two years last August, when 

 passing through the meadows here to my work 

 about a quarter to six in the morning, I observed a 

 crow pecking in a small pool formed in the walk by 

 the previous night's rain. Being curious to know 

 what he was so vigorously engaged with, I came 

 cautiously forward, and saw it was a crust of bread 

 which he was apparently softening in the water. On 

 my approach, he flew away, and lighted on the grass 

 some twenty yards off, and then commenced to peck 

 away with seeming pertinacity. I passed on for a 

 short distance, still keeping my eyes on him, when 

 he started again for the pool, tossed in the crust, and 

 turned it over two or three times in the water, at the 

 same time testing, as I think, the softness of the 

 crust. While thus engaged, another man coming up 

 disturbed the crow at his breakfast, whereupon he 

 lifted the crust, flew to some distance on the grass, 

 laid down the crust, opened up a tuft of grass with 

 his bill, put in the crust, and carefully drew the grass 

 over it again, and when concealed to his satisfaction, 

 immediately flew away. Now his purpose in steeping 

 the crust and hiding it in the tuft of grass I can 



understand, as I have no doubt he intended coming 

 back for his meal, when it would be in a condition 

 better suited for mastication ; but the question 

 comes, how was he to find out this particular tuft of 

 grass among thousands around it ? He took no note 

 of the locality, so far as I could observe. — J. IV., 

 Edinburgh. 



BOTANY. 



Albino Varieties. — Mr. J. Taylor's remarks on 

 this subject are so interesting that I venture to add 

 a little thereto, in the hope that others may be pro - 

 voked to give the benefit of their learning or ex- 

 perience. I noticed last year, not far from Simmons' 

 Yat, in the Severn Valley, a large patch of Ajuga 

 reptans. The whole of the plants bore white flower?. 

 There was no trace of the blue flower whatever. I 

 have observed Polygala vulgaris within four miles of 

 this city (Bath) bearing red, blue, and white flowers. 

 The plants bearing blue flowers, and those bearing 

 pink flowers, were growing on the same bank within 

 a few yards of each other. I found last year speci- 

 mens of Orchis morio presenting almost every shade 

 of colour, from the normal one to white. There 

 seems to have been so little written by English 

 authors on the subject of colour in flowers that I am 

 induced to quote verbatim two or three paragraphs 

 on the subject from the excellent new edition of Dr. 

 Goodall's " Physiological Botany " (Gray's Botanical 

 Text Book, vol. ii. New York and Chicago, 1885). 

 " The colours of petals and other coloured parts of 

 the flower," observes Dr. Goodall, "are dependent 

 either on the presence of corpuscles (the coloured 

 plastids) or of matters dissolved in the cell-sap. The 

 following account of the colouring matters in the very 

 common Viola tricolor is condensed from Strasburger. 

 A vertical section through a petal exhibits the epi- 

 dermis of the upper side as consisting of elongated 

 papillae, while that of the lower side has only slightly 

 rounded ones. Just below the epidermis of the upper 

 side there is a layer of compact cells, under which 

 are several rows of smaller cells with conspicuous 

 intercellular spaces. The cells of the epidermis of 

 both sides contain violet sap and yellow granules ; 

 the layer of compact cells under the epidermis of the 

 upper side contains only yellow granules. The 

 striking diversities in colour presented by different 

 parts of a given petal depend wholly upon combina- 

 tions of those two elements of colour : namely, violet 

 sap and yellow granules. In some places, which are 

 devoid of either of these elements, there are white 

 spots : at these places the light is refracted and 

 reflected by the intercellular spaces which contain air. 

 If the air is removed by pressure, the spots will 

 become transparent. The cell-sap in the parts of the 

 flower may have almost any colour, especially shades 



