■1C)Q [September, 



ANDRENA BUCEPHALA Steph. AND NOMADA BUCEPHALAE Perk. IN 

 DEVONSHIRE, AND NOTES ON THEIR HABITS. 



BT E. C. L. PEEKIXS, D.Sc, M.A., F.E.S. 



One da}'^ in the first half of last May, on the coast near Paignton, I 

 happened to come across the local Anch-enn hucephala and its still more 

 local parasite Nomada hucephalae. This WomaJa Avas wrongly con- 

 sidered by Smith and Shuckard to be the N. lateralis of Panzer, and 

 alsD wrongly by E. Saunders to be a mere variety of N. riijicornis L. 

 In the January No. of this Magazine {ante, pp. 12, 13) I have recently 

 discussed the specific characters and habits of the whole rvficornis group 

 of Nomada. 



In several years previously I had made special but unsuccessful 

 efforts to find A. hucephala — in fact, ever since 1 casually captured a 

 single 6 of its parasite a few years ago, — and it was hj the merest chance 

 that I found it this year. A Nomada seen hovering over a small bank 

 was recognized at once by the distinctive abdominal markings (con- 

 spicuous enough, as it hovered) as a female N. huceplialae. Before 

 an}^ attempt to capture it could be made, it had disappeared down 

 the burrow, Avhich it had been investigating in the usual manner of its 

 kind on the wing. A large glass-bottomed box having been placed over 

 the burrow, I walked aAvay to see if other sjjecimens of the parasite or 

 its host were to be found in the neighbourhood, for it is sometimes a 

 considerable time before a bee that has entered a burrow will come out 

 again, even in hot bright weather. Returning after some minutes, I 

 was much surprised to see about half a dozen of the Andrena fl3'ing 

 around or actually settling on the box, while as many more were to be 

 seen inside this, and no fewer than three females of the Nomada. The 

 returning specimens of the Andrena were heavily laden Avith pollen 

 and so were allowed to enter the burrow. Subsequentl}^ it was seen 

 that dozens of females w^ere carrying their store into this one nest. 

 All the short time that I could give to field-work was spent in 

 watching these bees, and altogether in May and June I visited the 

 locality on four occasions, spending an horn' or two there each time. In 

 all, three burrows of Andrena hucephala were found, two of which — one 

 being the original one — were quite close together, or not more than a 

 yard apart, while the other was placed in another bank, or slope, some 

 thirty or forty yards away. From the number of bees seen to enter 

 these three bm'rows and from the males observed flying round the 

 bushes within a few yards of them, I estimated that those females 

 whicli were using and the males which had emerged from these three 

 burrows amounted to at least several hundred and probably to not less 

 than a thousand individuals. When the species Avas at the height of its 



