Leptinotarsa decemlineata

Eggs
The yellow or pale-orange, elongate-oval eggs, are ca 1.2 mm long. They are laid in groups of 12-25 on the underside of potato leaves. The females glue them to the leaf by one end using a special secretion. The long axis of the egg is almost perpendicular to the leaf. Eggs within a mass tend to form irregular rows and hatch simultaneously.
Larvae
Body strongly convex dorsally, with large abdomen. Head, bearing 6 ocelli behind the antenna on each side and a pair of 5-dentate mandibles. Three thoracic segments, each bearing a pair of 3-segmented legs, plus claw. Abdomen 9-segmented. Colour changing with development, first instar cherry-red with shiny, black head and legs;later instars becoming progressively carrot-red, then pale orange in final instar.
Head, legs and posterior part of pronotum black to deep brown;two conspicuous rows of dark spots occur on the lateral aspects of the mesothoracic and abdominal segments 1 to 7, the uppermost surrounding the spiracles, and also segments 8 and 9 with dark dorsal plates. Setae when present are very small, some occur on the head, legs, pronotum, on the pigmented areas and ventrally. Spiracles small, annular with black peritremes and situated on the mesothorax and first 8 abdominal segments. Body length of full-grown larva about 15 mm.
A detailed generic diagnosis of Leptinotarsa larvae is provided by Cox (1982) and the first instar is described by Peterson (1951). The weights of the four larval instars are given by Balachowsky (1963).
Pupae
Yellowish, bearing short setae on low, conical, brown tubercles. Head bearing several short setae, mandibles apically unidentate. Thorax with pronotum bearing about 100 setae;meso- and metathorax much more sparsely setose;apices of femora bearing about 3-5 setae and apical tarsal segment 1 seta. Abdominal segments 1-6 with lateral expansion dorsal to spiracle, dorsally bearing about 48 short setae, laterally about 9 setae on large papilla ventral to spiracle. Apical abdominal segment bearing a single, brown, median, sharply-pointed urogomphus or spine. Spiracles situated on mesothorax and abdominal segments 1-8;peritremes dark brown, but pale on abdominal segments 6-8. For further details, see Cox (1996).
Adults
Head, pronotum and venter yellow-orange with black markings, legs and scutellum orange-yellow, elytra yellow-orange with five longitudinal black stripes. Apical segment of maxillary palpi cylindrical, rounded apically, shorter than preceding segment. Elytra punctate-striate, epipleura glabrous. Mesosternum not raised above level of prosternum. Profemora normal, third tarsal segment entire, tarsal claws simple, divergent, not fused basally. Body length 8.5-11.5 mm.
The genus was revised by Jacques (1988). A key to the North American species is given by Wilcox (1972) and Jacques (1985).