80 MONOGRAPHIA 



20. DOCOPHORUS COLYMBINUS. Denny. (Louse of the 



Diver.) 



Plate VIII. Fig. 8. 



Chestnut and shining ; head, with two dark semicircular 

 lateral fasciae ; metathorax transversely ovate, with a slight 

 angle behind ; abdomen ovate and pitchy. 



Head and thorax bright chestnut, or tawny, the former 

 obtusely triangular ; clypeus with a somewhat pyriform de- 

 pression, a pitchy-black impressed semicircular lateral fascia 

 before the antennae on each side, and two deep chestnut lines 

 extending upwards from the occiput ; antennae and trabe- 

 culee short and thick, pale yellow brown ; prothorax small, 

 transverse ; metathorax the width of the head, transversely 

 ovate, with an impressed margin, base slightly produced or 

 angular ; abdomen ovate, pitchy chestnut, segments nearly 

 equal, with a dark angular spot upon the lateral margin of 

 each, stigmatic apertures deep ; legs chestnut ; tibiae with 

 the apex fuscous. Length 1 . 



This species I have received from Mr. Selby, Mr. 

 Tweedy, and Mr. Heysham, taken on the Red-throated 

 Diver (Colymbus septentrionalis) upon which Bird I have 

 also found it several times ; my brother sent it from the 

 Black- throated Diver (C. arcticus), and Mr. Heysham for- 

 warded me a specimen found on the Northern Diver (C. 

 glacialis), which although rather larger than the generality 

 of the specimens occur, and of a bright chestnut, I still 

 consider only a variety, as I have seen specimens taken 

 from the Red-throated Diver quite as bright, although the 

 usual colour of the abdomen is pitchy. Had I an oppor- 

 tunity of examining a series of specimens from the C. gla- 

 cialis, I might probably have reason to alter my opinion. 



