6 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 124 



southeastward along the Savannah River to Chatham County on the 

 Atlantic Coast. Collecting in South Carolina may extend the range 

 into that state. 



Specimens of D. s. serrulatus from the southwestern limit of its 

 range — Santa Rosa, Walton, and Calhoun Counties, Fla. — present 

 a dark, smokey, castaneous venter that becomes reddish or castaneous 

 in Franklin County, throughout the remainder of Florida, and 

 throughout most of Georgia. The western border of the range of D. s. 

 serrulatus then appears to be the eastern margin of the Piedmont 

 Plateau. 



Dineutus serrulatus analis is somewhat more variable over its large 

 range than is D. s. serrulatus. The elytral apices of D. s. analis may 

 be obtuse at the sutural angle (fig. 6), but they usually are produced 

 (fig. 7). Both conditions can occur in a single series. The male pro- 

 femoral tooth usually is prominent (fig. 3), but in a single series it 

 may be either apparent or merely the truncation of a femoral carina 

 (fig. 4). The external apical angles of the protibiae are rounded (fig. 

 10). This character is more apparent in the male than in the female, 

 and in some female specimens the angle may even be distinct, but 

 never produced. Bronzing of the dorsum is the most common con- 

 dition, but specimens with a black dorsal surface are not uncommon. 



Dineutus serrulatus serrulatus appears to be more constant in its 

 characters than does the western subspecies. The elytral apices are 

 not produced (fig. 8), but occasionally a tendency toward that con- 

 dition may be seen in a few specimens with a more sinuous elytral 

 apex than usual (fig. 9); in fact, this is the case with both of the 

 type-specimens. The profemoral tooth of the male is always distinct 

 and acute. The shining castaneous venter varies somewhat. In western 

 Florida it appears uniformly darker, rather less reddish and slightly 

 more brown, but never approaching piceous. 



The differences in ventral coloration in species of Dineutus having a 

 light venter appear to be associated closely with the tissue underlying 

 the integument. The integument tends to be more or less transparent 

 in these forms, and the color is largely dictated by underlying fat, 

 muscle tissue, and internal organs that are darkened slightly by 

 various brown or reddish pigments in the integument. Heating the 

 specimens in water to relax them for genitalia extraction often de- 

 taches the underlying tissues from the integument, causing a darkening 

 in color. Preserving methods and materials also can alter color, and, 

 where the tissues are separated from the integument, the space sep- 

 arating them can be observed with correct lighting and magnification. 

 Other factors affecting ventral color are the pygidial sacs of the re- 

 pugnatory organ (see Brinck, 1955, for discussion of internal anatomy) 

 and the exudations of these organs and musculature of the genitalia. 



