184 ME. A. W. BENTSTETT OTST THE COTSTSTAJSTCT OF 



the number of species among whicli the visits were distributed, 

 and the colours of the flowers, which I have divided into four 

 groups, viz. : — E, red, pink, or purple ; B, blue or violet ; Y, yellow 

 or orange ; W, white. 



The number of observations I have been able to make is pro- 

 bably not sufficient to determine any general law with regard to 

 the constancy of insects in visiting flowers. As far as the results 

 go, they may be stated as follows : — 



The diiferent classes of insects show very great difference in 

 this respect. Butterflies show but little constancy, except in a 

 few instances ; but they would appear to be guided to a certain 

 extent by a preference for particular colours. The Diptera ex- 

 hibit greater constancy, though by no means absolute. A much 

 greater degree of constancy is manifested by the Apidse ; and 

 this becomes all but absolute in the Hive-Bee. It is an interest- 

 ing circumstance that this constancy appears to increase in pro- 

 portion to the part performed by th.e insects in carrying pollen 

 from flower to flower. A much larger number of observations is, 

 however, needed in order to determine with certainty any general 

 law ; and especially a careful microscopic examination of the 

 pollen attached to the proboscis, mandibles, legs, and underside 

 of the abdomen and thorax. 



As regards preference for particular colours, the Lepidoptera 

 paid, while under observation, 70 visits to red or pink flowers, 5 

 to blue, 15 to yellow, 5 to white ; the Diptera 9 to red or pink, 

 8 to yellow, 20 to white ; the Hymenoptera 303 to red or pink, 

 126 to blue, 11 to yellow, 17 to white. 



Lepidoptera. 



Obs. No. of species No. of visits paid and 



No, Name. visited. colour of flower. 



15. Piex'is Brassicse 2 R3, Rl. 



17. PierisEap* 3 B 1, R7, B 1, R 1, B 1, R3. 



18. „ 2 B2, R6. 



23. •„ 2 R7, Rl, Rl. 



42. „ 3 R2, R2, Wl. 



48. , 3 W1,R1,W1. 



49. „ 2 Rl, R4. 



69. „ 2 Rl, W2. 



16. Polyommatus Alexis... 5 R 1, R 1, Y 1, Yl, R 1, Y 1. 



21. „ ... 1 Y2. 



24. „ ... 1 Y2. 



1. Hippavcliia Janira ... 1 R7. 



2. „ ... 2 Y2, Yl. 



3. „ ... 2 Y4, Yl. 



7. Vanessa Urticse 1 Y (not counted). 



