248 Proceedings of the Royal Physical Society. 



XXVIII. — On Docophorus bassanas, Denny, and Lipeurus staphylinoides, 



Denny. By James Waterston, B.D., B.Sc. 



(Received 19th January 1912. Read 22nd January 1912.) 



In the Monographia . Anoplurorum Britannia: (London, 1842), Denny 

 describes and figures Docophorus bassana} 1 from the Gannet (Sula bassana), 

 and in dealing later with the genus Lipeurus, introduces as a new species 

 L. staphylinoides 2 from the same host. Piaget {Les Pediculines, Leide, 

 1880, vol. i.) treats L. staphylinoides as a variety of L. pullatus, Nitzsch. 3 

 " Le L. staphylinoides de Denny provenant d'une S. bassana me parait une 

 simple varied oil les taches de l'abd. male sont toutes transverses." 



The form named by Denny, D. bassana}, seemed to him so variable as 

 to merit two figures. After describing two stages he says, " I am induced 

 to consider these two insects, although differing considerably at first sight, 

 as the adult and immature state of the same species. I had drawn both 

 and committed them to copper under the impression that they were 

 specifically distinct, but since, upon examining many specimens taken from 

 recent birds, I find such varieties in size, proportion, markings and colour, 

 as to convince me that the fig. 3 of plate 7 is nothing more than the last 

 moult but one; many specimens in still earlier stages exhibit a greater 

 diversity of appearance, and it is only by comparing a series that the identity 

 of the whole can be inferred, sometimes the fasciae are without the notch, 

 at other times pale brown and extending nearly across the abdomen." 



Piaget, who also evidently felt some difficulty in dealing with bassance, 

 places it, with brevimaculatus and dubius, last among the species of Docophorus 

 which he had personally examined. It forms, in his opinion, a distinct type 

 in the genus, but he adds that bassanas is " only half known " to himself, 

 presumably because he had seen but one sex. 



Through the courtesy of Mr A. M. Kodger, The Museum, Perth, I have 

 recently had submitted to me a series of Gannet parasites, amongst which 

 both the species under discussion are represented. There is one adult 

 male of L. pullatus, N., which is normal in having the first four abdominal 

 fasciae mesially divided. There are besides several females corresponding 

 exactly with Piaget's figure, and a number of other examples which are as 

 plainly the insect named bassanm by Denny. 



'..Pp. 110, 111, pi. vi. fig. 3, and pi. vii. fig. 4. 



2 Pp. 180, 181, pi. xv. fig. 2. 



3 P. 340, pi. xxvii. fig. 9. 



