82 PROCEEDINGS OF THE ACADEMY OF [1896. 



In Colorado, species of Perdita have been found at La Junta, 

 Fort Collins, Estes Park and Glenwood Springs. On August 12, 

 1887, I found a species at Cottonwood Creek, Pleasant Valley, Fre- 

 mont County, Colorado ; it was sent to Mr. Ashmead, but the species 

 WAS not determined. In my note-book I recorded that it was 3^ mm. 

 long, head black, thorax gray, abdomen red-brown; surely it was a 

 new species, different from any herein described. A few species of 

 Perdita have been found in other parts of the west — three in Lower 

 California, three in California, three in Nevada. Two are known 

 from Texas, one from the State of Chihuahua, Mexico. Two 

 vaguely from Mexico. 



In the Eastern States, Perdita is represented by only two species, 

 odomaculata of the northern region, from Illinois to New Hamp- 

 shire ; and obseurata in the south, Georgia and Florida. One of 

 the Rocky Mountain species, alhipennis, extends northeastward to 

 South Dakota. 



As regards vertical distribution, one species, spJueralcece, extends 

 from the Mesilla Valley to Santa Fe, but the Santa Fe form is an 

 easily distinguishable race. P. lepachidis extends unaltered from 

 Socorro to Santa Fe ; and zebrata and chamcesarachcB extend from 

 Albuquerque to Santa Fe. P. austini and bigelovice extend from 

 the Mesilla Valley to Albuquerque. 



THE FLOWERS VISITED. 



It may be laid down as a general rule that each species of Perdita 

 visits normally but one species of flower, but occasional speci- 

 mens may be found on flowers to which they do not normally belong. 

 The exceptions to this rule are found in P. odomaculata visiting 

 Solidago, Coreoj^sis and Aster ; P. cladothricis visiting various 

 Compositee as well as Cladothrix ; P. pedidis visiting Pedis, Tribulus 

 and Wedelia; P. fallax visiting Bigelovia, Verbesina and Pedis; 

 P. phyiiiatce visiting Bigelovia and Gutierrezia ; and P. seviicrocea 

 visiting Solidago, Bigelovia and Gutierrezia. 



In the case of several uniques, it is not certain that they normally 

 belong to the flowers on which they were found. Thus a single P. 

 pnlchrior was found on Bigelovia at Las Cruces, and it would have 

 gone in as a Bigelovia species but for its previous discovery on 

 3feiitzelia at Albuquerque. In the Mesilla Valley, toward and at 

 the base of the Organ Mountains, are many species of flowers which 

 should by all analogy have their species of Perdita. But theoppor- 



