98 Mr. D. Sharp's revision of the species 



This differs only from Hydrophilus collaris, Fab., by 

 the fact that the green marks I have spoken of in 

 H. collaris as being grafted on to the posterior portions 

 of the 2nd and 3rd green lines on the wing-cases are in 

 T. proximus not joined thereto, but are continued for- 

 wards on the yellow interstice as separate (more or less 

 broken up) lines. In T. mexicanus these intercalated 

 lines exist entire, not broken up as in T. proximus. 

 Whether this peculiarity of markings really indicates a 

 distinct species I cannot say, but it appears to me at any 

 rate an interesting local race ; and I could not say 

 whether, if a race, it is an offset from Tropisterniis 

 mexicanus or horn Hydrophilus collaris. 



The individuals in my possession are from old French 

 ^collections, and some of them are labelled " approxi- 

 matus," but I have preferred a shorter trivial name. 



4. Tropisterniis mexicanus, Cast. 



Cast., Hist. Nat., ii., p. 54 ; Sharp, Biol. Cent. Am., 

 i., pt. 2, p. 55, pi. ii., f. 3. 



Central America, from Mexico to Nicaragua. 



In this species there are six elongate green lines on 

 each wing-case ; in some individuals these lines are con- 

 nected together into one large mass of dark colour by 

 an infuscation or discoloration of the surface, and in 

 such specimens there usually exists also a dark cloud 

 round the central mark on the thorax ; examples in this 

 state resemble extremely the North American H. strio- 

 latus, but the punctuation of the wing-cases is less fine 

 in this latter species. The sculpture of the epipleural 

 margin is quite as indistinct in T. mexicanus as it is in 

 Hydrophilus collaris. 



5. Hydrophilus striolatus, Lee. 



Lee, Proc. Ac. Phil., 1855, p. 357. 



North America. (Southern United States) ; (Mexico?). 



This is very closely allied to T. mexicanus, but the 

 punctuation of the wing-cases is evidently coarser and 

 more distinct, and the sculpture of the epipleural margin 

 can be traced further forwards ; the yellow intervals 

 separating the green lines are usually veiy small, and 

 frequently cannot be detected at all ; the metallic colour 



