1988] 
Wolfe — Hydrovatus methlini 
329 
Table 1. List of species of Dytiscidae examined only for abdominal structure. 
Hydroporinae 
Canthyporus hot tent otus Gemminger and Harold 
Celina grossula J. LeConte 
Celina hubbelli Y oung 
Celina imitatrix Young 
Deronectes striatellus J. LeConte 
Hydroporus aulicus J. LeConte 
Hydrovatus pustulatus Melsheimer 
Hydrovatus sp. (from Sri Lanka) 
Laccornis conoideus J. LeConte 
Laccornis deltoides Fall 
Laccornis etnieri Wolfe and Spangler 
Laccornis lugubris (Aube) 
Laccornis copelatoides Sharp 
Methles cribatellus Fairmaire 
Oreodytes quadrimaculatus (Horn) 
Queda compressa Sharp 
Colymbetinae 
Agabus spinipes Sharp 
Colymbetes sculp tilis Harris 
Lance tes sp. 
Dytiscinae 
Dytiscus fasciventris Say 
The terminal tergum of specimens of Q. compressa Sharp is most 
similar to morphotype 1 . 
Morphotype 3. (Figs. 2A-D). In this morphotype, the seventh 
and eighth terga are modified in both males and females. Tergum 8 
is extremely acutely pointed posteriorly and also consists of a dorsal 
and ventral lamina. The ventral lamina (Fig. 2B) is a thin, flexible, 
triangular structure that is similar to that of Hydrovatus; the lateral 
edges are fringed with setae and curved dorsally thus forming a 
broad channel into which the dorsal lamina rests. 
The dorsal lamina (Fig. 2A) is quite sclerotized, rigid, and overall 
rather wishbone-shaped. Posteriorly, the structure is somewhat 
trifid with the medial portion extremely prolonged, laterally com- 
pressed, and apically acute; the apicolateral portion is densely 
setose. Anteriorly, the dorsal lamina extends as a pair of diverging 
thin apodemes. Each apodeme expands anteriorly into a club 
shaped apex and extends anteriorly underneath the seventh tergum 
all the way to the posterior edge of the sixth tergum (Fig. 2D). 
