401 

 looked to the interested observer 111 .-it in the 



colony as to where that i^rain >hould be, a case illust ra I in:/ tin- U 

 tions ot' instinct in developing 'team work.'' 



Lar^c centipede-. Scolo^cndrn, arc quite (oinmoii, often entering 

 houses and l>ein^ much feared; though their bite i- by no nie,< 

 seriou> as repre.sented. The whip M orpion, T/n'lyf>hnnu\. "is rarely 

 met with on the mesa. Though ])robably poisonous, its |,it- is also 

 ly exaL:u;eratcd in popular belief. " (Watson.) Tarantulas, Lycosa, 

 are somewhat more common than the last but much less so than the 

 centipedes. Their bite is more serious than any of the above, lni ; 

 not dangerous to most people." (Watson.) 



Rio Grande Semi-desert Formation. Hot and dry. Gutierrezia 

 Association. The big clumsy sand-cricket, Stenopelmatus fasciatus, 

 is common under stones, etc. Several species of the tenebrionid sub- 

 family Eleodina? are characteristic. One of these beetles, Eleodes 

 lonz'icollis, when held, can squirt an ill-smelling fluid to a distance of 

 right inches. The large black tenebrionid beetles, Eusattus convexus, 

 " form a very large and characteristic feature of the fauna of this region. 

 They are true children of the desert. Their elytra are grown together 

 and to their backs, an adaptation to the fierce sand storms of the mesa. 

 These wind storms drifting sand and gravel with them are a source of 

 grave danger to the fauna of the region, even to man himself. The 

 author has several times been caught out on the mesa when one struck 

 the region with its usual suddenness and has stopped to observe the 

 behavior of the animals. The prairie horned larks sought the shelter 

 of the friendly arroyo banks. (The author has picked up these birds 

 on the mesa during one of these storms. They were so exhausted by the 

 buffeting that they had received that they made no effort to escape.) 

 The digger wasps climbed into the Gutierrezia bushes and hung on for 

 dear life with all of their feet wrapped about the stem, an attitude that 

 they also assume during a shower; the snout beetles on the other hand 

 backed down off the Gutierrezia and sought shelter in the ground; the 

 woolly bears and other caterpillars curled up under the shelter of tufts 

 of grass; most of the lizards sought their holes as did the harvester 

 ants; but these Tenebrionidae went about their business as usual entirely 

 oblivious, apparently, of the storm. Their heavy bodies kept them 

 from being blown away and their heavy coat of chitin (it is hardly 

 possible to force a heavy insect pin through some species) defied the drift- 

 ing wind. In their disposition not to be too particular as to what they 

 eat they again show that they are true children of the desert. Anything 



26 



