1922.] 275 



oil tlie margin of a wet ditch, only a few inches from water, on 

 September 24th, 1921. 



A male and female of B. lapidariiis were taken in copula on the 

 ground in a grass field, near Bethesda, at G.30 p.ai. during August 

 1920. 



The perforation of the corolla base of flowers by B. terrestris has 

 not been noted in the districts examined, though it does not follow that 

 it may not occur, as I have often seen it in other areas. 



Some instances were noted of Bombi passing from one species of 

 flower to another, although, as a rule, they adhere to one species at a 

 time; examples were: — (1) B. agroriivi, 24.iv.21, from Viola canina 

 to Geranium robertianum ; the same species, 29.viii.20, visited StacJ>i/s 

 germanica, Galeopsis sp., Shirley Poppy, and back to Galeopsis ; 

 B. hipidarius, 24.viii.20, from Centanrea nigra to Hieracium ; B. Jior- 

 forum, Julv 1919, from Foxglove to Prunella vulgaris. Similar cases 

 are quoted by J. H. Lovell (" The Flower and the Bee," 1920, p. 92). 



Chittenden (Ann. Appl. Biol., May 1914, p. 42) calls attention to 

 the importance of the numbers of visits paid by an individual insect, 

 and states that a specimen of B. terrestris paid 48 visits to different 

 flowers in the course of 10 minutes. I made notes on this subject on 

 April Gth, 1921, in a plum orchard at Tregarth, Carnarvonshire. 



B. pratorum visited 10 flowers per minute on the average. 

 B. terrestris ,, 8 „ „ „ „ 



B. lucoruni ,, 10 ,, ,, ,, ,, 



One other point seems worthy of mention, the apparentlj'^ irregular 

 (not to say capricious) manner in which certain flowers are visited by 

 Humble-Bees. For instance, Fuchsia, Weigela, and Ehododendron 

 were practically deserted on June 2nd and 3rd, 1920, in the college 

 grounds, wliile there were a few visitors to Azalea and on Cotoneaster 

 only Golletidae were present. At the same time Escallonia swarmed 

 with B. terrestris, lucorvm, lapidarius, agrorum, and others. Near 

 Bethesda, on August 29th, B. terrestris, lueorum, and agrorum were 

 concentrated upon Fticlisia. No doubt a careful investigation as to the 

 factors involved would clear up such cases; probably the maximum 

 nectar flow was to be obtained from Fscallonia at the moment. 



Bangor. 



Aufftist 1922. 



