1974] Evans, Matthews J & Callan — Rubrica surinamensis 345 
entrance, then turn around and back in, as occurs commonly in other 
sand wasps. Much use is made of the mandibles in biting soil around 
the entrance, the wasp often producing a loud buzz in the process. 
When the burrow is nearly full, it can be seen that the soil is 
packed in with rapid blows of the tip of the abdomen, which is 
turned downward and forward and moved in a somewhat circular 
pattern. Finally, small pebbles may be dragged backward over the 
entrance. 
Nest Associates 
The fly Raviniopsis spinosa (Hall) (formerly in the genus Pachy- 
graphomyia ) (Sarcophagidae) , is a constant nest associate of Rubrica 
surinamensis in Trinidad, where it was first recorded by Vesey- 
Fitzgerald (1940). It has been noticed by EMC many times in 
Trinidad, and also on the Paria Peninsula of Venezuela (Callan, 
1954). The fly was also common at Cali, Colombia^ usually to be 
seen perched near a nest entrance on the alert for a wasp returning 
with prey. One was seen to dash quickly upon a fly just being 
brought into a nest, presumably larvipositing upon it. Six of 37 cells 
dug out at Cali contained maggots, 2-4 per cell. In every case the 
wasp larva appeared healthy, and several had attained full size. 
None of the maggots found in cells at Cali were reared through 
to adulthood, but at St. Augustine, Trinidad, on 14 March 1943, 
EMC found a nest containing a maggot along with a large wasp 
larva. The maggot was fed on dead houseflies and pupated on 16 
March, producing an adult R. spinosa on 28 March. On another 
occasion, at St. Augustine, a female R. spinosa was captured and 21 
minute first instar larvae were squeezed from her abdomen. Some 
of these larvae were placed on a large Rubrica larva, but they made 
no attempt to attack it. Five of the maggots were placed separately 
in small glass vials. Two or three dead houseflies were put in each 
vial and others were subsequently added. Two of these larvae eventu- 
ally pupated, producing adult R. spinosa 12-14 days later. 
Other species of Sarcophagidae evidently also act as inquilines in 
Rubrica nests. One of several flies taken from nest entrances at Cali 
was identified as Sarcophaga sp. Three flies reared from nests at 
St. Augustine on 2 December 1941 proved to be Sarcodexia sterno- 
dontis Townsend. It should be noted that Sarcodexia, Sarcophaga, 
and Raviniopsis are all members of the subfamily Sarcophaginae, 
although it is Miltogramminae that are usually found associated with 
the nests of Hymenoptera. 
