Hawkmoths of Brazil by Alan Martin
IDENTIFICATION KEY: ISOGNATHUS
1. Small mostly brown Isognathus
I. allamandae female: more pointed wings than australis and with a smaller and more clearly defined dark marginal band to the hindwing.
Wing (male and female): 27-
I. allamandae male: similar to female but with two narrow black forewing dashes.
I. australis female: shorter and broader forewings than allamandae. The dark hindwing marginal band is broader and less uniform in width than allamandae. Note also the pale post-
Wing (male and female): 26-
I. australis male: similar to female but with two short thick black forewing dashes.
2. Larger mostly brown Isognathus
I. leachii: generally darker forewings than swainsonii and with narrower and more uniform width hindwing marginal bands. The forewing dashes can be quite broad and extensive.
I. swainsonii: the classic swainsonii have generally paler forewings than leachii with more white scaling visible, and the dark hindwing marginal band is wider and less uniform in width. However some believe that the variation of swainsonii that occurs in southern Brazil should be split to become Isognathus brasiliensis.
I. scyron: thorax and forewings russet-
Wing: 30 -
I. mossi mossi: generally dark body and wings, with shorter rounded forewings. Found only in the north of Brazil.
I. menechus: distinctive broad forewing dash in the shape of an uneven stretched letter ‘m’ or ‘n’.
I. excelsior: distinguished from all other Isognathus species by the pure white underside to the abdomen. Found only in the north of Brazil.
I. occidentalis: similar to excelsior but with a pale brown underside to the abdomen rather than white. Found only in the north of Brazil.
3. Heavily patterned and dark Isognathus
I. caricae caricae: unmistakable with very dark forewings and yellow hindwings with black veins.
4. Isognathus with black hindwing veins