Eggs of the boll weevil are pearly white, usually elliptical, and approximately 0.8 mm long by 0.5 mm wide. Legless white grubs hatch from eggs; they have light brown heads approximately 1 mm long. The larva, as it feeds and grows for 7 to 14 days, exhibits a ventrally curved, crescent form, with the dorsum strongly wrinkled and the venter smooth. The pupa is white at first but turns brown as it develops for 3 to 5 days. The adults are initially light in color but darken with age to colors from reddish brown to gray; depending on abundance and nature of food, they range in size from about 2.5 to 7 mm. The dark snout of this weevil is about half as long as the body (Fig. 1). Three forms (Mexican boll weevil, southeastern boll weevil, and thurberia weevil) have been separated by using characters ranging from morphological profemoral width/length ratios and spermatheca shapes to analysis systems relying on molecular biology.

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