Rhinoceros Beetles in West Africa — Hoyt 
445 
Data obtained from the examination of field- 
collected larvae of N. sawagei indicated that 
there were five instars. The length of the fourth 
instar period of a single larva provided with 
a constant supply of small cetonid and Oryctes 
grubs was slightly over 2 weeks. The pupal 
period was 10 days. Several of these scaritid 
larvae lived 3 weeks without food. Considerable 
difficulty was experienced in hatching the eggs 
laid by captive adult beetles and rearing their 
larvae in the laboratory because both stages were 
frequently attacked by fungus. In the case of the 
larvae this fungus appeared to be a Metar- 
rhizium. 
The adult beetles mated readily in small ciga- 
rette tins (14 cubic inches in capacity), which 
were partly filled with moist rotten palm fiber. 
The eggs of these scaritids were found in the me- 
dium, there being one egg per beetle. In a single 
instance a second egg was laid 3 days after the 
first had been discovered. The eggs were oval 
in shape, about 2 mm long and V 2 mm wide. 
When laid they were sticky, and quickly became 
covered with bits of frass. This made them hard 
to find and, as no special attempts were made to 
discover them, no doubt many were missed. 
Adult female beetles which were dissected con- 
tained a maximum of four large eggs. 
Both the adults and larvae of N. savagei 
readily attacked, killed, and consumed cetonid, 
Oryctes, and other dynastid grubs of a size up 
to 10 g in weight (the size of an early third 
instar Oryctes larva). The larvae of the palm 
weevil, Rhynchophorus phoenicis F., were of- 
fered to the adult beetles and while these were 
usually killed, the beetles did not seem to feed 
on them to any extent. 
The adult scaritids survived for long periods 
without food, the maximum period noted being 
about 4 weeks. 
The adult beetles are winged and are strong 
fliers. Occasionally they are attracted to lights 
at night. 
The sexes are readily distinguishable. The 
mandibles of the male are elongated, and the 
distal portion is without well-developed hori- 
zontal teeth. Those of the female are slightly 
broader and shorter, and the left mandible has 
a broad, flattish, horizontal inner tooth which 
forms a subapical notch. The mandibles of the 
males are apparently adapted for grasping the 
female around the back of the head during 
copulation. However, both sexes feed readily on 
scarabaeid grubs. 
The sex ratio was found to be 1 to 1. Usually 
one or two adult beetles were found in the 
debris of an oil palm, but on one occasion four 
were taken in a single site. No figures were 
obtained on the sexes collected from individual 
palms; the ratios were calculated from total 
field collections. 
The majority of the beetles were collected 
from the oil palm debris; however, a fairly large 
number of both adults and larvae were also 
found in the rotten Raphia trunks. The fauna 
of the oil palm trash and of the standing rotten 
trunks was, with one exception, identical. The 
exception was Oryctes sjostedti, which was only 
found breeding in the oil palms. However, it 
seems safe to regard this site as a sort of elevated 
trash heap rather than an unique environment. 
At Umudike the beetles were kept in round, 
50-cigarette-size tins. At first only one adult 
was put in each tin, but later, to conserve space, 
two were placed in each container. Rotten palm 
fibre was added to each tin to give the beetles 
something in which to dig. After about 1,400 
specimens had been collected at Umudike, they 
were taken to Ibadan and there packed for ship- 
ment. Plywood trays divided by partitions into 
2 -inch cubes were used to hold the beetles in 
transit. Each cube was partly filled with moist 
wood wool. A single scaritid was placed in each 
compartment, and the tray was covered with 
-inch-mesh wire screen held down with 
staples. Three or more trays were then packed 
into a heavy polythene bag to prevent loss of 
moisture. The trays in their bags were packed 
into heavy cardboard boxes which were wrapped 
with paper. From 4 to 6 boxes made up a ship- 
ment. The insects were sent from the Ikeja air- 
port via Paris to Fiji by air freight. Cigarette tins 
were used as containers for the first two or 
three shipments, but these were heavier than 
the plywood trays. 
During the shipments, there were always 
more beetles than containers. Usually, - enough 
males were discarded to bring the sex ratio to 
1 male to 3 females instead of the normal 1 to 1. 
An ideal container would have been an alumi- 
