1922.] 273 



The following table is based on that given by Knuth (p. IGO) 

 witli some additions and modifications from measurements made by 

 myself, Mason (Journ. S. E. Agric. Coll., Wye, 1907, pp. 178-lSO), and 

 others : — 



Leii(/th of Tovfjue in Bouibus, shoicuuj variation. -^ 



1. B. tevreniris 7 -9 mm. .. 9-11 mm. 



2. B. lapidarius 9-5-] 4 „ .. 9-5-14 „ 



3. B. pratonim 8-12 „ . . 9 -14-5 „ 



4. B. derhamellus 12 -13 „ ..13 -14 „ 



5. B. acjrorum 12-13 „ . . 13 -15 „ 



(}. B. hortorvm 7 -K! „ ..12-21 „ 



(the Iiijilier figures are from Kimlh) 

 7. Apis mellifica G mm. 



Within the areas examined the Bombi, la^^idariiis, terresivis, 

 htcorvm, Iwriorum, and agroriim are abundant, although Stephenson 

 found terrestris scarce about Aberyst\v3^th in 1915-10. B. pratontm 

 lilcewise was scarce at Aberystwyth, but proved to be fairly common in 

 A^rth Wales in ] 920-21 and on the Lancashire Coast in 1919. 

 B. soroi'nsis was scarce at Aberystwyth. 1915-16, and also occurred 

 sparingly in Carnarvonshire, 1021. Mr. C. H. Mortimer reports it 

 common but very local at Aberdovey in August, where also B. jonelhis 

 and B. lapponicns were both similarly reported from Aberdovey, but 

 were rare in Carnarvon, etc., and also at Aberystwyth, 1915-16. 

 B. derliamelhis is local. B. sijlvarum and helferanus were found by 

 Stephenson to be fairly frequent about Al)erystwyth, but the former is 

 not reported from North Wales, while the latter is by no means common. 

 Of JatreilleUits I have only a single record, near Eethesda on July 11th, 

 1920. 



With regard to the interpretation of the mass of data collected, it 

 is at once obvious that the species showing the widest ranges of activities 

 are to-restris, lucorum, and affrorum. Of these the last-named shows 

 the longest series of flowers visited and seasonal activities. I am not 

 able to record it as a useful w^orker of fruit blossoms, Avith the exception 

 of Easpberry. During the period May-August, however, it was the 

 chief visitor of Eed Clover, while Alsike, White Clover, and Lotus 

 corniciilatus were also included to a very considerable extent. It w^as 

 also very abundant on Gentaurea nigra, Galcopsis, Teucrium, Prunella, 

 etc. 



B. terrestris and B. lucorum are considered by Sladen ("The 

 Humble-Bee ") to be closelv related, and in this connection it is interesting 

 to compare their work, which shows close similarity in the kind of 



