VOL. 54, NO. 1, JANUARY 1978 
67 
mandibles by the base of their antennae. Each time the female ap¬ 
proached the nest carrying a cockroach and the male was present he 
climbed on her back and attempted to mate with her. She brushed 
him off as she entered the nest but when she left it he again climbed 
on her back and they mated. Then she flew off and he remained by the 
nest. The female apparently spends no time at the nest aside from 
initial preparation, provisioning and closure. 
A strange male approached the resident male, as it was sitting by 
the nest and the resident attacked it. They rolled off the tree grap¬ 
pling and buzzing into some leaves below but the strange male soon 
broke away and flew off. The resident male then returned to the nest, 
proceeded to groom and then wandered around the tree trunk investi¬ 
gating every movement, although curiously it never seemed aware of 
a Centris labrosa Friese nesting nearby in the tree (Fig. 3d). 
The first sealed nest found (Fig. 3a) was opened to determine how 
many cells it contained and other data. Each nest, at least at this site, 
consisted of one cell (Fig. 1, 2). It contained 15 nymphal cockroaches 
ranging in size from 12 to 40mm and weighing an average of 0.55g, 
giving a total of 8.2g of prey per egg. Two species of cockroaches 
were used, probably: 2 Eublaberus distanti Kirby and 13 Archimandrita 
tessellata Rehn (Blaberidae). Unfortunately the egg was never found. 
The cockroaches appeared to be unparalyzed and could move about 
freely in the cell except that they were packed in too tightly. The nest 
was never closed until finished so it is unclear what keeps the cock¬ 
roaches in the nest. When the provisioning was completed, the 
female plugged the entrance tunnel with 1.5 to 2.0cm of mud of about 
the same color and texture as that on the adjacent trail. Apparently all 
the female does to initially prepare the nest is to enlarge it, no other 
modifications are made and mud is only used to plug the entrance. It 
takes her between three and four days to complete the nest. 
The tree in which these nests were built had been dead for more 
than three years. Many animals were nesting in it aside from Dynatus 
including a large colony of Nasutotermes termites, an eumenid wasp 
and two species of Centris: C. labrosa Friese and C. vittata Lepeletier. 
Despite this the wood was still incredibly hard. The tree itself was 
17cm in diameter and 3m tall. 
Another interesting aspect noted was that this species excretes 
large amounts of water. This is not ordinarily reported in literature 
about sphecid wasps but it is commonly seen in some bees. This 
could be due to the large size of these wasps which makes it more ob¬ 
vious. The male did leave the nest several times a day for half an hour 
or more, probably to visit nectar producing flowers. A. S. Menke col¬ 
lected individuals at the flowers of a specific shrub in Venezuela 
(Bohart and Menke, 1976). 
