INSECT ECOLOGY 399 



as in ponds. Large numbers of diverse insects, many of which come 

 to the surface for air, both in the adult and the young stages. Water 

 scorpions, Ranatra; creeping water bugs, Pelocoris femoratus; small water 

 bug, Zaitha fluminea; water boatmen, Corixa; predaceous diving beetles, 

 Dytiscidae; water scavenger beetles, Hydrophilidae. The gilled aquatic 

 insects are the May fly nymphs, Ccenis and Callibaiis; damsel fly 

 nymphs, Ischnura verticalis; dragon fly nymphs, .^Eschnidae and 

 Libellulidae ; these utilizing the vegetation as resting-places or clinging- 

 places, or as a means of creeping to the surface to transform. 



Tension Lines. Margins of bodies of water, swamps and marshes, 

 ind temporary ponds are on the border line between land and water. 

 The classification of the communities of such tension lines of overlapping 

 environments is often difficult. (Shelford.) 



Along the margins of young ponds and lakes is an area which is 

 characterized by being made up of wet sand or mud which is submerged 

 at high water and moist at other times. Here we find springtails 

 (especially Podura aquatica) , shore bugs (Saldidae) , many tiger beetles 

 (Cicindelidae) and numerous small flies. The ground beetle (Bembidion 

 carinula) and numerous scavengers (Staphylinidae, Histeridae, etc.) 

 are common because the beach is often strewn with dead animals which 

 have floated ashore. (Shelford.) 



In Shelf ord's Animal Communities there are extended accounts of 

 communities of streams, lakes, ponds, prairies, and forests. 



COMMUNITY RELATIONS IN NEW MEXICO 



The notes that follow on the insect ecology of New Mexico are taken 

 from an interesting report by Professor J. R. Watson. They are 

 here arranged under four of Livingston's vegetational areas. 



Northern Mesophytic Evergreen Forest Formation. Douglas 

 Spruce Association. Poor in insect life. Some thirty species listed. The 

 carpenter ant, Camponotus pennsylvanicus , is common here and in the 

 yellow pine association, but was not seen outside of the mountains. 

 The butterfly, Grapta zephyrus, is also limited to these two associations. 

 The familiar mourning cloak butterfly, Vanessa antiopa, is present. 

 Yellow Pine Association. About fifty species of insects listed. Machi- 

 lis sp. The hemipteron Oncometopia later alis is confined to this asso- 

 ciation. Circotettix undulatus is very rare outside of this association; 

 it makes the loudest noise of any grasshopper in the region. Another 

 locust, Arphia acta, noteworthy for its loud crackling noise, is common, 

 and descends into the cedar association. 



