46 
Psyche 
[March 
doubtedly conspecific with the Texas specimen, differing only as 
follows: 
No white on scape; apical segments of palpi only slightly dusky; 
white band on anterior margin of pronotum briefly interrupted 
medially; all of lower metapleuron white; gastric tergites 4-9 more 
broadly white; posterio-dorsal black band of hind coxa percurrent; 
first flagellomere 6.3 as long as deep at apex; malar space 0.83 as 
long as basal width of mandible; ridge on lower prepectus extend- 
ing about 2/3 the distance ventrad to prepectal carina; hind tro- 
chantellus 0.47 as long as its trochanter in dorsal view; punctures 
of second gastric tergite sparser, mostly separated by more than 
2.0 their diameters. 
Among its relatives, lamentaria most resembles C. banchiformis 
of the eastern United States and the two nearly replace one another 
geographically since banchiformis ranges down to San Antonio, 
Texas within less than 500 km. of the Valley. Lamentaria differs 
from banchiformis mainly in its black and white (instead of mostly 
fulvous) femora and in having the lower metapleuron and propo- 
deal dorsum strongly wrinkled but with at most obscure intercalated 
punctures (instead of with numerous discrete punctures). The two 
species probably stem from a common ancestor which, during 
warmer and wetter Tertiary times, ranged uniformly from Mexico 
up along the Gulf arc into eastern United States but then was frag- 
mented by Pleistocene glacial maxima into southeastern (Florida) 
and southwestern (Mexico) isolates, which have practically reestab- 
lished contact during the present moderately warm interglacial. 
The unique Texas female was netted as it flew about a tangle of 
Serjania vines in gallery woods along the Rio Grande. This is the 
same habitat and same general area where C. compacta and C. 
vallis also were collected. 
Genus Mesostenus 
12. Mesostenus gracilis Cresson 
SPECIMENS EXAMINED: 6 females, BENTSEN PARK ( Malaise : 1 fe- 
male, 1-15 V’76); BOTANICAL GARDEN {Net: 1 female, 16-30 V’74; 
Malaise: 4 females, III ’74). 
HABITAT: Herbaceous undergrowth in Celtis lindheimeri-C. pal- 
lida woods. 
DISTRIBUTION: U.S. and northern Mexico. 
