i6o 
The Ohio Naturalist. 
[Vol. VII, No. 8, 
work on our American Papirius. While the genus is of very 
little economical importance, yet it holds a unique position with 
respect to the other Thvsanura, and to the insects in general. 
It is the intention to use this paper as a foundation for future 
work along systematic and phylogenetic lines. 
Characters of the Genus. 
The characters which separate our apterous, or primitive 
wingless insects, into the principal groups or sub-groups are, as 
a rule, fairly well defined. The first attempt at classifying our 
apterous fauna was made by Linnaeus in 1746, when he placed all 
the springtails ( Collembola) in the genus Podura. 
In 1796 these were combined by Latreille with the genus 
Lepisma and elevated to the rank of an order under the name 
Thvsanura. He distinguished two genera of the Lepismidae 
and two of Poduridae , separating out the globular shaped species 
under the name Smynthurus. This term is now used to distin¬ 
guish the family whose characteristics may be defined as follows: 
Body globular, slightly longer than broad; the saltatorial organ 
present, attached to the penultimate abdominal segment; and 
provided with a ventral sucker. 
This family, Smynthuridae , varies considerably from all the 
other groups of apterous insects in having a round, almost globu¬ 
lar body. The antennae are very much knobbed, and consist 
of four segments, with the exception of the genus described by 
Bourlet, which he termed Dicyrtoma, having eight jointed an¬ 
tennae. However, some doubt the validity of this genus since 
the characters are very doubtful as the knobbed, four jointed 
antennae of Papirius might easily be mistaken for an eight- 
jointed one, nevertheless this genus will here be retained. 
The family, Smynthuridae , is divided into three genera which 
are very closely allied and separated entirely on antennal char¬ 
acters as follows: 
A. Terminal segment of antennae short, with whorls of haris. 
Papirius. 
AA. Terminal segment of antennae long, annulated. 
B. Antennae with eight segments, abdomen with two tubercles. 
Dicyrtoma. 
11B. Antennae with four segments, abdomen without tubercles. 
Smynthurus. 
The genus Papirius is distinguished by only one character, 
that of having a short terminal segment to the antennae with 
whorls of hairs, and being considerably annulated. The genus 
was proposed by Lubbock in 1872, having Podura jusca Geoffrey, 
as its type, and characterized by Lubbock as follows: “Body globu¬ 
lar, antennae four-jointed, terminal segment short with whorls 
of hairs. Saltatory appendage comopsed of a basal portion and 
two arms.” 
