BEES OF GREAT BRITAIN. 49 



the size ; they attach themselves to the hairy parts of the bees, 

 as the metathorax, and the sides of the thorax beneath the wings. 

 What these pediculi really are, is at present involved in complete 

 obscurity ; Mr. Kirby regarded them as insects in their perfect 

 condition, naming them Pediculus Melittce. I have frequently 

 observed these creatures in considerable numbers in the flowers 

 of Ranunculus acris, as many as twenty or more in a single 

 flower, about the month of April ; and I think always before the 

 usual time for meeting with the larvae of Meloe. I have found 

 them on various species of bees, usually on those which are most 

 pubescent, as Andrena fulva, thoracica, and nigro-cenea ; also 

 commonly on Melecta armata, Anthopkora retusa and pilipes ; 

 this circumstance would appear to confirm, or indicate a con- 

 nection between the insects, and from analogy we might readily 

 conclude that this Pediculus must be a parasite on some species 

 of bee ; but we have nothing in support of this supposition, and 

 against it we have the following observations : Mr. Newport 

 has shown that it cannot be the larva of Meloe cicatricosus, and, 

 as well as myself, has proved that it cannot be that of M. viola- 

 ceus or of M. Proscarabceus ; and since the only other species of 

 Meloe, the M. variegatus, does not occur near London, it appears 

 certain that it cannot be the larva of any species of that genus, 

 unless it be discovered hereafter that the larva of Meloe not only 

 increases in size in its hexapod state, but that it also changes 

 from bright orange to black. 



Another circumstance which induces me to hesitate in adopt- 

 ing an opinion of the Pediculus being a larva at all, is the fact, 

 that on opening some cells of Anthophora retusa, which I dug 

 up on Hampstead Heath, I found two living specimens of the 

 hexapod in the same cell as the perfect bee ; it is certainly pos- 

 sible that they might have subsisted on a portion of the food 

 laid up by Anthophora ; but here was no change of condition, 

 and how came they into the cell ? I am inclined to think that 

 they, being insects in their perfect condition, came there exactly 

 in the same way as we find Forficula, having forced an entrance, 

 which I did not observe, and that they were in quest of food, 

 seeking what they might devour. 



In the determination of the species of the genus Andrena 

 much difficulty will be met with, the similarity of the males of 

 many species being so great, that nothing short of a long and at- 

 tentive study of them, combined with out-of-door observations, 

 will enable the student to discover those niceties of distinction 

 which are easily detected by the practised observer ; these 

 difficulties are considerably enhanced by the changes in colour 

 to which they are subject. The species of the first division 

 which are usually more or less red are very inconstant ; speci- 



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