CHRYSOMELIDAE. 



187 



are completely black, except that the mouth-parts, antennae and tarsi remain 

 brownish fuscous. 



Head with vertex convex ; front divided by a transverse impressed line or 

 constriction above roots of antennae ; surface strongly and closely punctate, 

 punctures in some cases being confluent with one another and producing ridges ; 

 edge along upper border of eyes deeply impressed. Eyes strongly convex. 

 Antennae extending slightly beyond 

 middle of elytra ; first segment long 

 and club-shaped, second small, thick- 

 ened, third slender, about twice as 

 long as second, fourth always longer 

 than third, although relative lengths of 

 third and fourth segments vary to a 

 certain extent ; fifth and following 

 segments about equal, apical segments 

 apparently very slightly thickened. 

 Prothorax broader than long, some- 

 what narrowed in front, posterior 

 lateral angles acute, each of the four 

 corners with a fine seta, upper surface 

 convex in centre and sloping on each 

 side, more so in front ; sculpturing 

 varying considerably ; entire surface 

 closely covered with punctures, which 

 are somewhat elongate and in many 

 specimens coalesce, producing oblique 

 longitudinal ridges ; this ridged con- 

 dition may be very pronounced, or 

 may be altogether wanting ; between 



these two limits various gradations may be seen. (The variation in the surface 

 structure of the prothorax renders the identification of a single example, in the 

 absence of a series, very difficult.) Scutellum almost pentagonal, fairly broad 

 though longer than broad, apex rounded ; surface closely punctate. Elytra 

 as broad at base as prothorax, with a fairly large area at base gently convex 

 (better seen when insect is held at certain angles) ; entire surface closely and 

 confusedly punctate. Under side as in generic diagnosis. 



Text-fig. 5. — Stygnobia variabilis, sp. n. x 18. 



