218 REPORT OF NEW JERSEY STATE MUSEUM. 



Family DYTISCID^E. 



These are the "diving beetles," and their larvae are known as "water 

 tigers" from their predatory habits, voracity in feeding and powerful 

 mandibles. The adults are also predatory, oval and somewhat flattened, 

 with rather short, stout swimming legs; the posterior longest and oar- 

 Jike. They live in water of all kinds and may often be seen in clear 

 springs rising to the surface, discharging a bubble of tainted air from 

 the anal extremity and then swimming again to the bottom. They are 

 interesting in structure and habits, but not of economic importance. 



CANTHYDRUS Sharp. 



C. puncticollis Cr. Staten Island V, 20 (Lg) ; Ocean Co. (Rob); Cape 

 May C. H. (W). 



C. punctipennis Sharp. Linwood (Rob); Clementon IV, 16, Petersburg 



V, 19 (Brn); Anglesea IV, V (Coll). Mr. Roberts says that "C. 

 bicolor" Say does not occur in New Jersey, and that the records 

 under that name in the last edition refer to this species. 



HYDROCANTHUS Say. 



H. iricolor Say. Recorded from Newark to the Delaware, and south to 



Cape May V, VIII, IX; taken by all collectors. 

 H. oblongus Sharp. Ocean Co. 1 spec.; it is common in Florida (Rob). 



LACCOPHILUS Leach. 



L. maculosus Germ. Common throughout the State in early spring and 

 again in fall; hibernates as an adult. 



L, proximus Say. Ft. Lee (Bt) ; Monmouth and Ocean Co. (Rob); De- 

 lair (Coll); Anglesea V (div). 



L. fasciatus Aube. Throughout the State in spring and fall; common. 



L. undatus Aube. Summit V, 1, Paterson IV, 2, Millburn IV, 30, West- 

 ville VI, 11 (Coll) ; Madison (Pr) ; Ft. Lee district (Bt) ; Monmouth, 

 Ocean Co. (Rob); Merchantville IV, 24 (Brn). 



* 



HYDROVATUS Mots. 



H. cuspidatus Germ. Ft. Lee district, Staten Island (Bt) ; Camden (Li); 



Atco V, 29, Brigantine VII, 25, Anglesea V, 28 (Brn); in stagnant 



water. 

 H. pustulatus Mels. Staten Island (Bt) ; Monmouth and Ocean Cos. 



(Rob); New Brunswick VI, 11, Anglesea V, 28 (Coll). 

 H. compressus Sharp. Anglesea V, 28 (Coll). 



DESMOPACHRIA Bab. 



D. convexa Aube. Great Piece Meadows V. 2, VIII, 22, Delair, Anglesea 



IV, 12 (Coll); Madison VII, 28 (Pr) ; Orange VI, 5, at light (Ch); 

 Camden (Li) ; in stagnant water. 



