JAMES A. G. REHN 
125 
Examination of a considerable nninber of specimens from both 
Americas shows the larger d.istal tibial spurs and the metatarsus 
of the caudal tarsi vary in length, relatively as well as actually 
We find in an extensive series from Spring Creek, Georgia, and 
a smaller lot from West Point, Nebraska, that the spurs range 
from equal to slightly longer than the metatarsus, while in the 
Rio ]\Iadeira material the spurs average faintly shorter than the 
metatarsus. We have seen one North American specimen^’ 
with the spurs shorter than the metatarsus. Shrivelling may 
have exaggerated the shortness of the spurs in the Rio Madeira 
specimens, as they show the pull of drying by having a somewhat 
arcuate form. Relative to the form of the free margin of the 
ultimate and penultimate ventral abdominal segments of both 
sexes, we find most decided variation. In the male sex the more 
usual type in North American specimens has the penultimate 
segment with a straight margin, the ultimate very faintly and 
shallowly arcuato-emarginate; from this type we find modi- 
fications with the penultimate segment having the margin 
flattened arcuate to very shallowly concave, the ultimate more 
deeply concave to almost truncate. The same sex in the Rio 
Madeira specimens always has the penultimate segment with a 
more or less arcuate margin, and the ultimate segment ranging 
from no more concavo-emarginate than in Spring Creek males, to 
deeply arcuato-emarginate, in fact sub-bilobate, with the lateral 
portions of the segment subcompressed. This latter condition 
is apparently due to the drying from alcohol, the degree of which 
it is almost impossible to correctly estimate. In the female sex 
the penultimate segment has the margin, in the Spring Creek 
series, varying from subtruncate with the faintest sort of nick 
mesad, to broadly and shallowly obtuse-angulate emarginate 
(more usual), while the ultimate segment has the margin truncate 
or truncate with a minute indentation, to faintly concave (more 
usual). The Rio Madeira females, from having the extreme 
type with a broad truncate emargination of the penultimate 
One male from West Point, Nebraska, in the Hebard Collection, has the 
metatarsi of the caudal limbs aborted, being represented by mere excrescences, 
such as found in the related genus Ellipes. 
Maryland; one male; (A. N. S. P.). 
TRANS. AM. ENT. SOC., XLIII. 
