292 THE AMERICAN NATURALIST. [Vor. XXXIV. 
Kallstremia grandiflora 'Torrey. — Very abundant in Phoenix; a very 
beautiful flower, which ought to be in cultivation. It is allied to the 
much less conspicuous X. drachystylis Vail. of the Mesilla Valley. 
K. grandiflora arizonica Ckll, with much smaller flowers and much 
shorter flower stalks, is also common at Phoenix. 
K. californica (Wats.) Vail. det. Wooton, was found near Buckeye. 
It has never been seen in the Mesilla Valley. 
Croton sp. — The common Croton of the Mesilla Valley is C. neomexicanus. 
At Phoenix I found in its stead a tall species closely allied to C. texensis, 
but less leafy at the top, and with very much denser pubescence on the 
leaves. No description has been found to fit it, and it may be 
undescribed. 
Lycium gracilibes Gray. — Abundant in the Salt River Valley, taking the 
place of the Mesilla Valley Z. Zorreyz. 
INSECTS. 
Spherophthaima gloriosa (Sauss.) takes the place in the Salt River Valley 
of S. pseudopappus in the Mesilla Valley. This is a so-called “ velvet- 
ant,” covered with long white hairs. 
(3) Species entirely different from those of the Mesilla Valley. 
PLANTS. 
Cereus giganteus Engelm. — The giant cactus. 
Holacantha emoryi Gray. — The crown of thorns. 
Parkinsonia torreyana Wats. and P. microphylla 'Torrey. — The two 
species of palo verde. 
Hetherotheca subaxillaris (Lam.) B. and R.—A yellow flowered composite, 
very abundant throughout the Salt River Valley. Itis doubtless native, 
as I found two new bees (Perdita mellina Ckll. and P. heterothece 
Ckll.) specially attached to it. 
The above are conspicuous in the landscape ; no attempt was 
made to catalogue the less conspicuous forms. 
SCALE INSECTS. 
It is an interesting fact that allied or identical plants in the 
two regions under consideration are in certain cases infested 
by entirely different scale-insects. Thus: 
‘The Larrea in the Salt River Valley is infested by Dactylopius irishi Ckll. 
and Yachardia larree Comst., while the same plant in the Mesilla 
Valley produces Dactylopius steelii Ckl. and Towns., Zcerya rileyi 
Ckll. and Eriococcus larree Parrott and Ckll. — 
The mesquite (Prosopis velutina) in the Salt River Valley is infested by 
KXerophilaspis prosopidis Ckll. and Thiaspi arizonicus Ckll; 
