402 ENTOMOLOGY 



from the tender green seedling leaves of a Hoffmanseggia to a dead 

 member of their own species is good. They collect in large numbers 

 about the carcass of a dead mammal. They will come out from their 

 winter quarters under the rosettes of Yucca and other sheltered places 

 any time in winter if it is as warm as 60 F. They have been taken by 

 the author on January 15. On the other hand they seem somewhat 

 to shun the hottest hours of the day in summer, being then much more 

 noticeable toward sunset." (J. R. Watson.) 



In the shallow depressions or "draw" in the mesa above the place 

 where a definite arroyo develops, there is found a society of which 

 certain quick-growing annual grasses are most conspicuous. "Here 

 and here only have I ever found this big, nearly wingless, 'lubberly 

 locust' (Brachystola magna), a good illustration of an insect restricted 

 to a very limited habitat. " (Watson.) The grasshopper, Heliastus 

 aridus, is particularly abundant in these arroyos, where its mottled 

 colors agree perfectly with the gravelly surface. 



Chrysothamnus Association. Occupying such rapidly eroding and 

 hence unstable situations as the dissected edge of the mesa and the 

 higher gravelly parts of the valley of the Rio Grande, this is the most 

 xerophytic (inhabiting hot dry places) of the associations. The charac- 

 teristic tenebrionid beetle, Cysteodemus wislizeni, is very common in 

 colonies, which are spread over much ground. The ambush bug, 

 Phymata erosa fasciata is very abundant; it is almost perfectly concealed 

 in yellow blossoms, as those of golden rod, where it occurs more com- 

 monly than in white blossoms. The clear- winged moth, Calesesia 

 coccinea, is exceedingly abundant on Hymenopappus during the third 

 week in May; its conspicuous colors blending perfectly with those of the 

 blossoms of this plant. The insect disappears by the first of June. 

 The magnificent noctuid moth, Erebus odora, is occasionally taken. 



The sand dunes are entirely barren of vegetation and of insect life 

 except for a species of digger-wasp, Bembex, which here finds conditions 

 favorable for its colonies. "All the specimens of the scorpion (Buthus) 

 that I have seen have come from this association. Its sting is, to 

 most people, not nearly as serious as it is represented to be. Persons 

 that have experienced it say that for a short time only is the pain more 

 severe than that resulting from the sting of a hornet and that it does 

 not last as long. " (Watson.) In the Croton Society the short-winged, 

 tricolored, or "barber-pole" grasshopper, Dactylotum pictum, occurs 

 wherever its food plant, Croton texensis, occurs in sufficient abundance. 

 The walking-stick, Diapheromera femorata, is present also. It is, of 



