182 MT^. A. AV. BENNETT OF THE CONSTANCY OF 



on which they fed. Four observations (Nos. 46, 47, 57, 63) 

 were made on Eristcdis tenax. In two o£ them it showed but 

 little constancy ; in the third it confined itself to a single flower 

 {Seracleum Sjjliondylium), tlie flowers of which were both wMte 

 and pink : and th.e abdomen was found to be loaded with tbe 

 pollen of this flower only. In the fourth case it was also visiting 

 a single flower {AcMllcsa 3£illefolium), and almost the whole of 

 the pollen in the abdomen appeared to be of this kind, intermixed 

 with a few grains of two other species. SyrpJius clypeata was 

 also observed four times (Nos. 22, 36, 55, 58); in one case only 

 was it constant in its visits to a single flower. The pollen-grains 

 in the abdomen were in one instance examined, and found to 

 consist of two kinds in about equal quantities, belonging to 

 widely separated natural orders, the Compositae and Labiatae. 

 Although the Syrphidse are constantly hovelling over and settling 

 on flowers, their function of conveying pollen is probably small 

 compared to that of the Hymenoptera, their object in visiting the 

 flowers being not to carry away the pollen, but to consum^e it. 



By far the majority of my observations (40) were made on the 

 visits of Apidse, and the greater number of these (33) on various 

 species of Bomlus or Humble-Bee ; and here I regret that igno- 

 rance of the specific distinctions in this difiicult genus detracts 

 materially from the value of what I observed. In four instances 

 (Nos. 10, 51, 52, 60) was a Humble-Bee observed to visit as many 

 as three distinct species of flower on the same visit, and to a 

 large extent irrespective of colour. In six instances (Nos. 6, 

 37, 38, 39, 41, 65) the number of species visited while the insect 

 was kept in sight was two ; and in all these instances the colour 

 of the two flowers was nearly the same. In twenty-three 

 instances (Nos. 4, 5, 8, 9, 20, 25, 26, 29, 30, 31, 32, 33, 34, 35,40, 

 43, 44, 50, 53, 54, 62, 64, 66) the Bee confined itself, while kept 

 within observation, to a single sJDecies ; but these plants were, in 

 the difi"erent instances, of the most various kinds and colours, 

 some shade of pink largely predominating, but we have also blue, 

 yellow, and white. The largest number of consecutive visits ob- 

 served was — to the apple 14, Malva moschata 15, Stachys JBeto- 

 nica 20, Stachys palustris 23, Wepeta Glechoma 25, and, again, 

 Nepeta Gleclioma (obs. No. 25) as many as 93 consecutive visits. 

 As the details of these observations will show, there can be no 

 doubt about this constancy being purj)osed, the flowers in qi;es- 

 tion in all cases growing intermixed with others, and the Bee fre- 



