ANOPLURORUM BRITANNLE. 185 



seven segments with a pitchy black three -sided character 

 on each lateral margin. 



Head sub-cordate, with two pitchy spots anteriorly, and 

 two triangular ones at the base, and a broad fascia behind 

 each eye, from which proceed a faint depressed line to the 

 occiput ; eyes prominent and yellow ; antennae long, rather 

 thick, the first three joints in the male very large ; pro- 

 thorax small, quadrate, with a black spot on each side; 

 metathorax as wide as the head, lateral margin very rotund 

 and black, base acuminate, with several long stiff hairs ; 

 abdomen oblong, the first seven segments marked on the 

 lateral margin with a pitchy-black three-sided character, 

 somewhat resembling the Hebrew letter 3 but variable ; 

 legs thick, pale yellow-white, superior margin pitchy; ante- 

 rior femora sub- triangular, with a dark spot at the apex ; 

 tibiae dusky ; tarsi chestnut. Length 2. 



Of this species I have seen but three specimens, two of 

 which were found on the Canada Swan (Cygnus Cana- 

 densis), in Norwich, and communicated by my brother, 

 and one on the Goosander (Mergus Merganser), by Mr. 

 Heysham at Carlisle. It approaches very nearly to the 

 Nirmus stenopyx of Dr. Burmeister, but as the colour of 

 that species is not recorded, I could not decide upon their 

 identity with that degree of certainty I could have wished 

 I therefore thought it better to give it a specific appellation 

 than a wrong synonym. 



3. ORNITHOBIUS ATRO-MARGINATUS. Denny. (Louse of 

 the Canada Swan.) 



Plate XXII. Fig. 3. 



Pearly-white and shining ; head obtusely panduriform ; 

 abdomen with a narrow black margin. 



Head and thorax pale yellow-white, the former obtusely 



