EXPLANATION OF PLATE XLIX. 
Fic, 40. Pelobius tardus, lateral view. 
41. Orthopterus smithi, lateral view (reversed). 
42. Gyrinus natator, dorsal view. 
43. Orectochilus dispar, ventral view. 
43a, »» » lateral view of median lobe. 
44. Hydrophilus piceus, dorsal view. 
45. Laccobius ytenensis, dorsal view. 
46. Cyclonotwm subdepressum, dorso-lateral view. 
46a. 33 5 , median lobe (ventral face up). 
47. Berosus signaticollis, lateral view. 
48. Silpha atrata, lateral view, with sac evaginated. 
Descriptions on pp. 491-495 and (Silpha atrata) p. 508. Explana- 
tion of the letters used uniformly on pp. 481-483. 
