Notes on identification of the cactus bugs, Chelinidea, in the U. S.
Unfortunately, most photos aren't clear enough to show identifying characters in adults. The most important thing to see clearly is the head and "neck" region and underside of femora (almost always missing in photos). If your cactus bug has keeled femora, and you want it identified, you'll need to hold the bug and photograph underside of front and rear femora so that the spines are clearly visible and photograph the head looking straight down upon it (not angled).
For nymphs, we're missing information about the two less commonly encountered species (C. canyona and C. hunteri).
Here, I have put together a visual guide.
Chelinidea canyona
- jugae bluntly pointed and near the length of the tylus (holotype)
- head with dark stripes adjacent to pale midline stripe
- under surface of front femora bearing distally two or three small teeth
- otherwise, resembles C. tabulata
- Nymphs with greenish body, reddish-brown head, pale yellowish legs. Needed are photos of adults and nymphs together.
- holotype
- TX, AR
Chelinidea tabulata
- jugae acutely pointed and extending well beyond the tylus (BG image)
- femurs with anterior longitudinal ridge
- anterior pronotum with a distinct tubercle on each side of head, lacking a notch at base
- under surface of front femora bearing distally a double row of teeth, decreasing in prominence proximally, and totaling from five to nine, teeth
- head lacks dark stripes adjacent to pale midline stripe
- nymphs green with light tan legs and antennae
- TX, AZ, CO, CA, UT
Chelinidea vittiger
- femurs rounded, lacking ridge
- anterior pronotum with a very short tubercle on each side of head with distinct notch at base or almost absent altogether
- nymphs green or brownish red with black heads, legs, and antennae
- Widespread; wherever prickly pear occurs
Chelinidea hunteri
- Anterior pronotum lacking tubercles, but with a cylindrical collar set off from the rest of the pronotum by a deep incision
- We are lacking in knowledge of appearance of nymphs. Needed are photos of adults and nymphs together. Recently, @abstinence_enthusiast has documented adults and nymphs on same cactus. Based on this, nymphs evidently green with legs/antennae tan at base and reddish or blackish distally.
- AZ, TX
1924 paper describing each species:
Hamlin, J. C. (1924). A review of the genus Chelinidea (Hemiptera-Heteroptera) with biological data. Annals of the Entomological Society of America, 17(2), 193-208.
1969 paper suggesting that canyona = tabulata
Mann, J. (1969). Cactus-feeding insects and mites. Bulletin of the United States National Museum.