234 MONOGRAPHIA 



2. TRINOTON LURIDUM. (Louse of the Duck and 

 Merganser.) 



Plate XXII. Fig. 2. 



Chestnut, shining and pubescent ; head obtusely trian- 

 gular; clypeuswith two black fasciae on each side; abdomen 

 cylindrical, flat, with transverse bifurcated bands like the 

 preceding, but more distinct ; legs very thick. 



Trinoton luridum. Nitzsch. Germ. Mag. iii. p. 300. Steph. Cat, pt. ii. 

 p. 334. Trinitum luridum. Burmeister Handbuch ii. pt. ii. 441. 

 Louse of the Teal. Redi. Expe. pi. xii. Albin. Aran. pi. 46. 



Head pale chestnut, obtusely triangular, base somewhat 

 trilobate; clypeuswith two short oblique black fasciae which 

 sometime coalesce, a broad uncinate band from the orbits to 

 the occiput united at the base, vertex concave, temporal 

 region pale exteriorly; prothorax obcordate, the anterior and 

 lateral reflexed margin pale yellow-white, a black sub-lobate 

 fascia on each side, centre with a depressed line and slightly 

 rugulose ; mesothorax with the lateral angles produced, base 

 fulvous ; metathorax with the basal margin and a longitudi- 

 nal space in the centre fulvous, and a black transverse basal 

 and humeral fascia finely punctured ; abdomen cylindrical, 

 pubescent, much flattened, depressed down the centre, su- 

 tural and lateral margins fulvous, transverse bands chestnut, 

 terminating in a black bifurcation on each side; legs fulvous, 

 very thick, the superior margin pitchy ; tibiae flat, with nu- 

 merous long hairs. Length 2 lines. 



This insect approaches very near to the preceding, so 

 much so that it is difficult in a description to make the 

 specific distinction appear evident. When the two species 

 however are viewed together, the distinction is very mani- 

 fest; the uniform difference in size is perhaps the most 

 striking, though the greater breadth of the head, more ob- 

 scure colour, ovate abdomen, and greater convexity of the 



