June, 1907.] 
American Species of Papirius. 
i 77 
13. Papiruis opalinus Folsom. 
1896. Papirius opalinus Folsom. 
Prevailing color, orange-rufous or ferruginous. Head; first 
two antennal segments, anal tubercle, and legs pale orange-och- 
raceous. Head with a few short bristles on front, vertex almost 
naked, swollen dorsallv. Antennae shorter than the body, 
from three fourths to one-half as long according to age; basal 
segment twice as long as broad, naked; second three or four times 
as long, knotty, and hairy toward the epex; third purple, four 
or five times the basal in length; distal end knotty, and hairy; 
terminal segment purple, one and a half times as long as basal, 
lanceolate with whorls of white hairs. Eye spots black, often 
quadrate. Body, regular, elongate, oval in dorsal outline; an¬ 
terior dorsum naked, translucent orange-ochraceous with a broad 
and median shading of green due to chlorophyll in the stomach; 
posterior dorsum and sides orange-rufous to dark ferruginous 
often with a tinge of maroon; posterior dorsum with short, white 
bristles upon minute brown orange - ochraceous spots; anal tuber¬ 
cle hardly visible from above; ventral surface pale yellow, with 
three pairs of buff, yellow tubercles; a small round tubercle on 
either side of the manubrium; a large oval oblique one either side 
of the middle; a narrow oblique pair anterior to these. Legs 
slender; femur with short, sparse bristles; tibia pale distally, 
stout spines at moderate intervals. Claws white, very stout; 
superior claw of almost uniform width, little-curved towards the 
apex, six toothed; inner edge with a tooth at the middle and an¬ 
other midway between it and the apex; two pairs of lateral teeth 
similarly placed near the outer edge; inferior claw two-thirds 
as long as the other, triangular in shape, tipped with a short 
bristle, inner edge sinuate or straight with a short bristle one- 
third from its base. Furcula short, reaching to the ventral tube; 
manubrium sparsely hairy; dentes twice as long, stout, pale or¬ 
ange-rufous with short lateral bristles and several longer ven¬ 
tral bristles at regular intervals; mucrones white, one-fourth the 
dentes in length, oblong finely serrated beneath, apex rounded. 
Ventral sucker pale orange-ochraceous, the tube and filaments 
together one-fourth as long as the antennae. Length, maximum, 
1.3 mm. Habitat: reported by Folsom from a green house, 
Cambridge, Mass. Found in company with P. vittatus. 
The description was taken from a large number of species, 
types of which were placed in the Museum of Comparative 
Zoology. 
Explanation of Plates. 
Plate XI. 
Enlarged drawing of P. unicolor, showing the insects in their natural 
environment. 
Plate XII. 
P. unicolor: 1, antennae; 2, claw; 3, eye spot; 4, tenaculum; 5. 
ventral sucker and filaments; 6, spring. 
