THE CACTUS BEES; GENUS LITHURGUS. 
T. D. A. COCKERELL. 
THE common cacti (Opuntia and Echinocactus) of New Mex- 
ico and adjacent regions are freely visited by bees, the females 
carrying pollen and undoubtedly aiding cross-fertilization. Pro- 
fessor Toumey, who doubtless knows more about cacti in a 
state of nature than any other man living in this country, has 
observed and reported the bee visits, without, however, identi- 
fying the bees. He has, however, also observed that most of the 
common cacti (Opuntia) about Tucson, Arizona, propagate by 
means of falling joints which take root, and not by seed ; and, as 
he showed me in his cactus garden last year, certain species 
have almost lost the power of producing seed. The cactus side 
of the matter will, I trust, be fully elaborated in due time by 
Professor Toumey, and I only refer to it now to bring forward 
the interesting fact that we have a group of plants which are 
in large part independent of sexual reproduction, but which 
at the same time possess flowers undoubtedly adapted to bees, 
and visited by a series of bees more or less peculiar to them. 
The explanation of this will, I think, be given by Professor 
Toumey, but in the meanwhile it will be useful to record the 
bee visitors. The following are the Lithurgus records for New 
Mexico: 
(1) Lithurgus echinocacti Ckll., 1898.— Two females at 
flowers of Echinocactus wislizenit, one at Mesilla Park (campus 
of Agricultural College), August 22 (Ckll.), one at La Cueva, 
Organ Mountains, September 4 ( Townsend). 
(2) Lithurgus gibbosus Smith, 1853 (n. syn. compressus, 
Smith, 2). — Our form has clearer wings than Smith's type. 
Las Cruces, at flowers of Opuntia engelmanni, May 26,49, 
May 25,19; May 24, 14 ; also observed many other times ; 
both sexes, but especially males, also common at flowers st 
Chilopsis linearis (Bignoniacez), May 31 and June 5; Mesilla, 
487 
