1970] 
Matthews £sf Evans — Sericophorus 
427 
Sericophorus relucens Smith 
According to Rayment (1955b), S. relucens is one of the com- 
monest and most widely distributed Sericophorus species in Austra- 
lia. However, in contrast to nests of the gregarious S. viridis, nests 
of S. relucens were never found in abundance. Indeed, all were 
discovered when the female was observed to return suddenly to a 
spot and disappear into the ground. The largest number of nests 
found in a given locality was three at 8 miles north of Peak Hill, 
N.S.W. (AM 112-114) on 11 December 1969. Here S. relucens 
nested in a flat area of rather coarse and moderately packed sand, 
at the base of eroded slag heaps of an abandoned mining operation. 
Other wasps nesting here included Bembix lamellata Handlirsch, 
B. raptor Smith, Bembecinus hirtulus (Smith), and Cerceris minuS- 
cula Turner. Additional single nests were found about 2 m above 
flood level on the west bank of the Murrumbidgee River at Pine 
Island Reserve, 10 miles south of Canberra, A.C.T., on 10 January 
1970 (AM 152) and on the south bank of Baker’s River, 5 miles 
S. Machay, Qld., on 2 May 1970 (AM 232). 2 Both were in 
moderately friable loamy sand with sparse vegetation. Nests of 
Bembix trepida Handlirsch, Bembecinus hirtulus (Smith), and 
Prionyx globosus (Smith) occurred in the same general area at 
Pine Island Reserve, and Bembecinus egens (Handlirsch) and 
Bembix raptor nested commonly at the Mackay site. 
Nest Structure. — The five excavated nests were of typical seri- 
cophorine form, consisting of a vertical main shaft 8-13 cm long 
and one or two cells at the end of short 2-3 cm long lateral tunnels 
frim the bottom of the main burrow. Typical nest profiles are 
illustrated in Figures 3 and 4. The relatively inconspicuous mounds 
or tumuli encircling the nest entrances measured 2. 5-3.0 cm across. 
Those of the Peak Hill nests were marked by accumulated piles of 
wind-blown plant debris, consisting mostly of dried Eucalyptus 
inflorescence parts (Fig. 10). All of the Peak Hill nests were situ- 
ated adjacent to sticks which littered the soil surface and appeared 
to act as miniature windbreaks. 
The most cells found in any nest was two, and it seems likely 
that this is the maximum number per nest made by this species. Sup- 
porting this was the fact that no cells containing mature larvae or 
cocoons were ever found; cells always contained fresh flies. Typically 
both cells were situated at about the same depth and on opposite sides 
Specimens were collected at all three localities and found to compare 
very favorably with the type specimen of relucens Smith, which we studied 
in the British Museum (Natural History). 
