252 THE BLOWFLIES oF NortH AMERICA 
but spines smaller, less pigmented, and seemingly less variable 
in distribution; segment 12 smooth on dorsal surface except pos- 
teriorly. Tubercles around stigmal field not nearly so prominent 
and much smaller than in sericata; outer pair on upper border 
distinctly larger than inner tubercles and more than twice as 
large as median ones; inner pair on lower border less than one- 
half as large as the other two pairs; relative position of tuber- 
cles similar to that in wWlustris; tubercles in anal protuberance 
about twice as large as the larger ones on the lower border of 
the stigmal field. Posterior spiracles (pl. 41, D) small and 
broad, usually broader than long; apertures short; peritreme 
without inner projections. Cephaloskeleton (pl. 41, C) small, ap- 
proximately 1.0 mm. in length, this being considerably smaller 
than in other species; pharyngeal sclerites comparatively short 
and broad. Anterior spiracles with five to six branches (in 64 
spiracles 40 had 5 branches, 24 had 6); portion of anterior 
spiracle external to cuticle approximately one-half as long as 
internal pigmented trunk. 
Like all the species of Phaenicia in North America, pallescens 
is a typical saprophage. If the larvae are fed decaying meat the 
species may be easily reared from egg to adult in the laboratory. 
The larval stage lasts about 72 hours under favorable tempera- 
ture conditions. The prepupal stage of pallescens lasts but a 
relatively few hours during the warmer periods of the year. The 
pupal stage may be as short as 6 or 7 days during the summer 
months, but emergence may be delayed for several weeks or even 
longer in cold weather. 
Adult. Phaencia pallescens is essentially a southern species. 
While sericata and pallescens may often occur together, the for- 
mer is found most abundantly in cooler climates, the latter 
throughout the southeastern part of the United States, particu- 
larly in the more humid areas. The adults are most numerous 
in market sections of cities where they may be easily collected 
upon decaying produce. In the vicinity of Washington, D. C., 
adults usually appear about the first week of June and remain 
abundant until about the first of September, although a few 
lingering specimens may be collected as late as November first. 
In southern Florida, especially in the vicinity of Miami, palles- 
cens is extremely abundant during the spring and summer 
months. Both sexes may be collected in numbers upon rotting 
fallen fruits and it is the abundant species of Phaenicia in meat- 
baited traps. 
