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
  • 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
  • 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.

Posted by pfau_tarleton pfau_tarleton, 27 December, 2021 15:45

Comments

Nice write up.

Have you seen anything on nymphs of canyona or hunteri? I still hesitate to ID the nymphs because I have never seen these. Though it's probably pretty safe in most places since these species are so uncommon.

Posted by ncb1221 about 1 year ago (Flag)

I haven't found anything on the nymphs, yet. I was hesitant also...but I figured if the adults haven't been seen in the area, we'd probably not be seeing the nymphs (not best practice...but sometimes I have an itchy trigger finger.

This 1924 paper describes nymphs of canyona--but the author had no experience with hunteri:
Third instar...."Head, reddish-brown; thorax greenish with black lines on either side just above coxae; legs and antennae pale yellowish; tip of beak and tarsi, black; abdomen pale dull green with two dorsal, yellow slits inconspicuous, and margins sawlike and blackened. "
https://academic.oup.com/aesa/article/17/2/193/13008?login=true

Posted by pfau_tarleton about 1 year ago (Flag)

Thanks for the info. I'll keep any eye out too for any different looking nymphs. Interesting bugs

Posted by ncb1221 about 1 year ago (Flag)

Except in the most obvious of cases, I have lately been refraining from identifying tabulata vs canyona. I don't think the characteristics for ID are as clear cut as some literature suggests. Much of my doubt is based on the discussion by Mann here in the discussion on canyona:

https://www.biodiversitylibrary.org/page/7891870

As it always tends to happen, the more you learn, the less you seem to know!

Posted by ncb1221 4 days ago (Flag)

@ncb1221, I haven't had a chance to read it yet (just got it today), but here's Herring's 1980 review of the cactus bugs:
https://drive.google.com/file/d/1XqOX61Daqox44degTh5GBhbXJQCKFusM/view?usp=sharing

Posted by pfau_tarleton 2 days ago (Flag)

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