Cephaloleia belti lays eggs on the petioles and rolled leaves of its host plants. This species lays eggs singly or in clusters of 2 or more eggs. During oviposition, eggs can be covered with frass (Garcia-Robledo et al. 2010).
Newborn larvae are white and translucent. Larval size after emergence is ca. 2.0 - 2.1 mm .Second instar larvae of C. belti turned pale orange (Garcia-Robledo et al. 2010).
Larvae pupate inside the second instar larval exuviae. The pupa display distinctive ornaments (see image gallery) (Garcia-Robledo et al. 2010).
Head, antennae, and scutellum black; pronotum yellowish with variable black markings; elytra black with yellow vitta. Head: vertex black, sparsely punctate; medial carina present; frons yellow; eyes protuberant, finely faceted. Antenna: black; antennomere 1 elongate, as long as 2-4 combined, robust, tuft of setae at apex; 2 transverse; 3 triangular, longer than 2; 4-6 transverse. Pronotum: wider than long; yellow with medial black vitta, vitta may be obsolete in middle; scattered large punctures laterally; side margined; anterior angle rounded, sinuate; pronotal length 1.16-1.27 mm (n=50); pronotal width 1.38-1.5 mm. Scutellum: black; sharply triangular; micropunctate. Elytron: black with yellow vitta and yellow lateral margin; apical margin black; from suture to 2nd puncture row dark, then through 5th puncture row yellow, then black through 9th puncture row, 10th puncture row to margin yellow; sutural stripe narrows and fades toward apex, fails to reach apex; apical segment of pygidium u-shaped in male, slightly acuminate in male; elytral length 4.8-4.96 mm; elytral width 1.93-2.04 mm. Venter: pro-, meso-, and metasterna yellow medially, black laterally; abdominal sternite 1 yellow medially, black laterally; sterna 2 and 3 black laterally, each has black stripe along apex, rest yellow; sterna 4 and 5 all black. Total length 6.4-6.56 mm; females are larger than males (Garcia-Robledo et al. 2010).
This species displays marked sexual dimorphism in the shape of the last abdominal sternite and the pygidium. The end of the last sternite in males is u-shaped. In females of C. belti, the last sternite is slightly acuminate (Garcia-Robledo et al. 2010).