Northern Prairie Wildlife Research Center
| Less than four pairs of midabdominal prolegs | go to group A |
| Four pairs of midabdominal prolegs | go to group B |
| Group A. Less Than Four Pairs of Midabdominal Prolegs | |
| One pair of midabdominal prolegs, on segments A6 | go to group A-1 |
| Two or three pairs of midabdominal prolegs, typically two pairs, one pair each on segments A5 and A6 | go to group A-2 |
| Group A-1.
One pair of midabdominal prolegs, on segment A6 All of the species of Group A-1 are Geometridae and nearly all of the Geometridae occur in this group. |
|
| Body wall with lateral flanges, warts or tubercles | group A-1a, see these photos |
| Body wall smooth | group A-1b, see subgroups |
| Group A-1b
subgroups: Body wall smooth Species of group A-1b are distinguished by color patterns. |
|
| Distinct spiracular line, body otherwise more or less uniformly colored or faintly patterned | see these photos |
| Dorsum a different color than subspiracular area | see these photos |
| Distinct subdorsal longitudinal lines | see these photos |
| Middorsal area with a stripe or dots | see these photos |
| Body with distinct patches of color | see these photos |
| Body with no distinct markings, more or less uniformly colored or evenly mottled | see these photos |
| Group A-2.
Two or Three Pairs of Midabdominal Prolegs Typically two pairs of midabdominal prolegs, one pair each on segments A5 and A6. Group A-2 consists of a few species of Geometridae and most of the species of semiloopers that are classified as plusiine noctuids. |
|
| Ventral fringe of knobby hairs, prolegs on A5 smaller than those on A6 | group A-2a, see this photo |
| Prolegs on A5 same size as those on A6 | group A-2b, see this photo |
| Group B: Four
Pairs of Midabdominal Prolegs One pair of prolegs on A3, A4, A5, and A6. Except for the Geometridae, all families in group B contain species that fit the description of this group. Species in this group are distinguished by the hairs on the thoracic and abdominal segments. |
|
| Without hairs in dense patches, existing hairs not sclerotized, not more than six hairs per segment per side above the spiracular line, hairs shorter than width of abdomen | go to group B-1 |
| Hairs in dense patches, not sclerotized, at least seven per segment per side above the spiracular line, hairs of various lengths | go to group B-2 |
| Hairs modified into sclerotized spines, scoli, or chalazae | go to group B-3 |
| Group B-1.
Without Dense Patches of Hairs Body not covered with dense patches of hairs, existing hairs are not sclerotized and not more than six per segment per side above the spiracular line; hairs are shorter than width of abdomen. Species in group B-1 are arranged by the appearance of the body wall and color patterns. Most of these species are either Gelechiidae, Noctuidae, Notodontidae, Papilionidae, Plutellidae, Sphingidae, or Tortricidae. |
|
| Body wall with short tubercles, small warts, asymmetrical swellings, or horns | group B-1a, see subgroups |
| Body wall smooth (except for monarch butterfly) | group B-1b, see subgroups |
| Group B-1a
Subgroups: Presence/absence of middorsal horn Species of group B-1a are distinguished by the presence or absence of a middorsal horn on A8. |
|
| Middorsal horn absent on A8 | see these photos |
| Middorsal horn present on A8 (Sphingidae) | see these photos |
| Group B-1b
Subgroups: Body wall smooth, except monarch butterfly Patterns in color on the thorax and abdomen are traits used to distinguish the subgroups. |
|
| Pattern of color in rings | see these photos |
| Longitudinal lines straight with at least one even edge | see these photos |
| Longitudinal lines wavy | see these photos |
| Middorsal markings irregular, with patterns of saddles, dashes, or spots | see these photos |
| Body marked with spots, or streaks, or reticulated | see these photos |
| Body without distinct markings, more or less uniformly colored or evenly patterned with faint markings | see these photos |
| Group B-2.
With Dense Patches of Hairs Body with dense patches of hairs, at least seven per segment per side above the spiracular line. Species are grouped by the location of dense hair patches and length of hairs. Numerous families contain species that fit the description of this group, including Arctiidae, Hesperiidae, Lasiocampidae, Lycaenidae, Lymantriidae, some Noctuidae, and Satyridae. |
|
| Hairs equal to or longer than half width of body | group B-2a, see subgroups |
| Hairs very short, whisker-like, sometimes barely visible | group B-2b, see subgroups |
| Group B-2a
Subgroups: Hairs of different lengths Species of group B-2a are distinguished by hair length and position of dense hairs. |
|
| Tufts of relatively short but very dense hairs occur middorsally on A1-A4 (Lymantriidae) | see these photos |
| Most of the longer hairs occur sublaterally (mostly Lasiocampidae) | see these photos |
| Entire body, or at least half of body length covered in hairs that are
longer than body width (mostly Arctiidae) |
see these photos |
| Less than half of body length covered in hairs that are longer than
a full body width (Acronicta: Noctuidae, Arctiidae) |
see these photos |
| Group B-2b
Subgroups: Hairs very short Species of group B-2b are distinguished by body shape and position of the head. |
|
| Body humped in profile, head concealed (Lycaenidae) | see these photos |
| Body not humped, head exposed (Hesperiidae, Satyridae) | see these photos |
| Group B-3.
With Sclerotized Spines Species are arranged by the shape of the spines. Most of these species are either Nymphalidae or Saturniidae. |
|
| Hairs modified into sclerotized spines with a single point tip (mostly Nymphalidae) | group B-3a, see these photos |
| At least some of the hairs modified into scoli, with a blunt end and multiple points (mostly Saturniidae) | group B-3b, see these photos |
U.S. Department of the Interior |
U.S. Geological Survey
URL: http://www.npwrc.usgs.gov/resource/insects/catnw/keyfam.htm
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Page Last Modified: Saturday, 02-Feb-2013 05:15:23 EST
Menlo Park, CA [caww54]
