E. arizonica, perhaps?
Iron-cross blister beetles; several together on prickly pear
Found on a running trail in High Park. Was already squished when I found it (of course).
Escarabajo con forma de hormiga, sin alas pero con medio caparazon.
Thanks to Dr. John Abbott for the ID to genus level from photos. Presume the large one is a female. The small one was following the large one and grabbing at and harassing it constantly.
Blister beetles are beetles (Coleoptera) of the family Meloidae, so called for their defensive secretion of a blistering agent, cantharidin. There are approximately 7,500 known species worldwide. Many are conspicuous and some aposematically colored, announcing their toxicity to would-be predators.