152 THE ENTOMOLOGIST. 



their nests in a colony. The parasitic Nomada altcrnata were 

 busy examining their burrows. They appeared extremely care- 

 ful, stopping at the mouth of the holes, with their antennae 

 directed forward, and carefully watching for any symptom from 

 within of the presence of the rightful owner. I saw the head of 

 an Andrena at one burrow, and it was presently withdrawn. 

 Very soon Nomada came and inspected the hole, but promptly 

 departed. However, in the case of one returning, A. trimmerana, 

 I thought the intruder had been caught inside. There was a 

 terrible scuffle at the mouth of the hole. It lasted just two 

 minutes, which appeared a long time as I watched it. Andrena 

 pulling with all her might, and something within which as 

 steadily resisted. At last, suddenly, out came something which 

 she thrust backwards beneath her between her legs, and which 

 rolled to the bottom of the bank, while she entered the burrow 

 triumphantly. I picked up the vanquished insect, which seemed 

 to be very seedy, and was surprised to find it was not a Nomada, 

 but a female Halictus rubicundus. 



I have watched females of Mellinus arvensis catching flies on 

 cow-dung. Mellinus ran about until it saw a fly, advanced to 

 within from two to three inches of it, paused for an instant, like a 

 dog pointing, as if it were taking aim, and then sprang forward, 

 rarely more than about two inches. The fly was often missed, 

 but, if caught, they both rolled over, Mellinus biting its prey. I 

 noticed it did not attack every species. The little flies, Sejisis 

 cynipsea, it passed by contemptuously. Lucilia cornicina it often 

 passed unnoticed, though I saw it attempt to catch several, only 

 in one case successfully, and then the fly was released immedi- 

 ately, seemingly none the worse, Mellinus running off apparently 

 disgusted at having made a mistake. Musca was greedily 

 seized. I did not see any " blue-bottles," which I know are a 

 favourite prey, but there was present a specimen of Mesembrina 

 meridiana which Mellinus avoided, giving it a wide berth, and I 

 frequently saw this big fly chase it for a few inches from one 

 place to another. I do no not know why this should be, for I 

 have often seen Mellinus carry off blue-bottles just, or nearly, as 

 large, and I have seen wasps attack this fly readily. 



Sometimes the tables are turned, and I have seen a little 

 Andrena minutula, when busily engaged rifling a dandelion-head, 

 pounced on by one of the bloodthirsty red " cow-dung flies." 

 The little bee was taken unfairly at a disadvantage, as it was 

 seized from above, and a desperate struggle ensued, until Andrena 

 reversed herself, when the fly decamped with most ludicrous 

 promptitude. 



Southpoint, Limes Road, Folkestone. 



