CARP 0 PH 1 L US LONGIVENTR 1 S 
IN SAGUARO BLOSSOMS 
(COLEOPTERA: NITIDULIDAE) 
By F. G. Werner 
University of Arizona, Tucson 
The common Nitidulid in saguaro blossoms is not Carpophilus 
pallipennis (Say), as is the case with other common cacti in southern 
Arizona, but C. longiventris Sharp. Adults reach the flower early 
in the morning of the one day they are open and swarm over the inside 
of the perianth, at the base of the stamens. By noon, elongate (1.06 
-1.34 x 0.22-0.25 mm.) white eggs have been deposited just under 
the lining of the perianth, parallel to the surface. These must hatch 
within 24 hours, because small larvae can be found the next day. The 
perianth and style gradually wither and usually drop from the develop- 
ing fruit within four or five days. By this time the larvae are mature. 
They change from white to pinkish-white and finally to tannish-white 
as they develop, probably partly because of the changing color of 
their food, pollen and probably other tissue, as decay progresses. The 
contents of the digestive tract show through the translucent body. 
Dead flowers on the ground rarely contain larvae, which must there- 
fore leave soon after the flower has dropped, or even before, presum- 
ably to pupate in the ground. The larvae do not enter the developing 
fruit and so probably have no effect on them. 
The adults are in most cases easily distinguishable from pallipennis 
by their dark elytra, but some small individuals have the elytra pale. 
In that case, they can be distinguished by the lack of small tubercules 
on the middle part of the hypopygidium, much sparser and less decum- 
bent pubescence on the pygidium and by the secondary sexual charac- 
ters given by Parsons (1943, Bull. M. C. Z., 92: 166-9). The large 
larvae are almost identical with those of C. floralis Er., as described 
and figured by Connell (1956, Delaware Agr. Exp. Sta. Bull., 318: 
1 7-21 ) . They appear to differ only as follows : prothoracic plates with 
about 10 setae around the edge and about 8 small pits alternating with 
them, plus 1-2 setae and 1-2 pits on the disc; caudal plate with indefi- 
nite margins, almost identical but with 2-3 small pits on each side; 
setae on caudal plate, and to a lesser extent on the dorsum of the 
thorax, slightly thickened apically, elsewhere tapering to a fine point. 
The differences are not great, and a comparison of specimens would 
be required to pick out those of diagnostic importance. 
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