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Identification Keys

LepIntercept Interactive Identification Key

The LepIntercept Interactive Identification Key is written in Lucid 3.6 and provided in Javascript format. The key will run in any modern web browser. This key is for beginning/casual users - please visit the About page for information on using the LepIntercept keys.

LepIntercept Interactive Identification (Lucid) Key


LepIntercept Dichotomous Keys

The LepIntercept Dichotomous Keys are written as traditional dichotomous keys with contrasting couplets. The keys are available as PDF files that can be downloaded and/or printed for use without a computer. These keys are for advanced users - please visit the About page for information on using the LepIntercept keys.

NOTE: Due to the continuing spread of H. armigera in South America, exercise caution when attempting identifications of Helicoverpa from that continent. There are no morphological characters to separate the larvae of H. armigera from H. zea. When in doubt, default to "Helicoverpa sp." instead of attempting a species-level ID. The following keys may not reflect the most recent H. armigera distribution in South America.

Key to frequently named lepidopteran larvae intercepted, or potentially encountered, at U.S. ports

Key to the identification of Helicoverpa armigera suspects intercepted at U.S. ports of entry

Identification guide to larval Heliothinae (Lepidoptera: Noctuidae) of quarantine significance

Morphological guide to known species of Diatraea intercepted at U.S. ports of entry from Mexico

Guide to species of Diatraea intercepted or potentially encountered at U.S. ports of entry using morphology and origin

Key to recognizing Spodoptera litura/littoralis intercepted at U.S. ports of entry

Key to larval Tortricidae intercepted, or potentially encountered, at U.S. ports of entry


Tips for examining larvae

Identifiers unfamiliar with Lepidoptera larvae should consult Stehr (1987) or Peterson (1948) for an overview of larval morphology and study techniques. In addition, an illustrated section on Larval Morphology is provided on this website. Larval characters can vary extensively, even in the same species, both between instars and in the same instar. Most of the characters discussed in the fact sheets and used in the keys are based on late or last instar larvae, and early instars of many species may be impossible to identify. When examining pinacula and setal number, be sure to look at both sides of the larva, as some specimens are asymmetrical. When an asymmetrical individual is found, use the highest number of setae when navigating the keys. Preservation of larvae can obscure characters, and even freshly preserved specimens may discolor and make color or pattern characters useless. All of the larvae illustrated in the fact sheets are preserved, so these specimens may appear very different from live and/or freshly collected individuals. It is also possible for pieces to break off specimens preserved in alcohol, and occasionally setae or other structures (e.g., the anal comb) may be missing because of breakage. Any determination made with the LepIntercept keys should be checked by an expert, and molecular analysis may be required to confirm identity in some cases.

Preserved larvae comparisons


Mandible and hypopharyngeal complex comparisons

Characters of the mandibles and hypopharyngeal complex can be quite useful in separating closely related species. In his review of larvae in the Hadeninae (Noctuidae), Godfrey (1972) stated that the "most reliable characters are associated with the hypopharyngeal complex, left mandible, length and shape of the dorsal abdominal setae, texture of the body integument, and the spacing of the metathoracic setae" (he found no difference between left and right mandibles). Other authors (e.g., Ahola and Silvonen 2005, [2008]; Beck 1999-2000; Passoa 1985) have illustrated mandibles and/or the hypopharyngeal complex for a large number of species. Here we provide a pictorial comparison of these structures for the taxa treated in LepIntercept. Please consult the Larval Morphology page for terminology related to these structures.

Mandible comparison

Hypopharyngeal complex comparison

  LepIntercept - An identification resource for intercepted Lepidoptera larvae
  by Todd M. Gilligan and Steven C. Passoa
  Identification Technology Program (ITP), Fort Collins, CO. Last updated February 2014.