A NEW SPECIES OF MACROTHRIX (ANOMOPODA, MACROTHRICIDAE) FROM CENTRAL MEXICO

Macrothrix mexicanus sp. nov. is described from central Mexico, a tran sition zone between the nearctic and neotropics. All localities where it was found are over 1800 meters above sea level. It shows many resem blances with M. laticornis, M. camjatae and M. rosea but is characteri zed by a persistent dorsal tooth on the valve keel, a spinous papilla on the basipodite of the antenna, the second thoracic limb with a long conical sensillum between scraper 1 and the gnathobase, the endopod o f trunk limb IV having two setae; the postabdomen with the dorsal marg in bilobed, and the distal segment of the seta natatoria which is unus ually long.