384 The American Naturalist. [ April, 
Description of Picobia villosa, sp. nov.— Length of body, male .7 mm. 
breadth .20 mm. The female is slightly larger. Body elongated, 
rather rotund; palpi abbreviated ; legs strong with five joints; tarsus 
of all the legs terminating in two chitinous Ctenidium or comb-like 
structures, the body of the latter thickened, convexed on the outer side 
straighter on side giving origin to the teeth, at point of attachment to 
tarsus the diameter is lessened and becomes rounded between the claws, 
the teeth constituting the comb are graduated in length being longest 
at free end, becoming shorter toward tbe articulation as shown in Fig. 
2, the teeth are also notched at their extremities the last tooth of the 
fourth pair having six denticles. Within the end of the tarsus, on 
each side, is inserted, by a stalk, an accessory delicate hyaline vertic- 
ally flattened appendage, see Fig. 2a, it is split up a part of the way 
into about nine sharp terminations which divaricate slightly ; they 
project to the outer side of the claws, their ends overhanging like 
fringe. At the end of the tarsus, corresponding to a point at the base 
of the combs, two curved claws are present as shown in Fig. 2. To the 
naked eye the body of this mite is whitish. Through the microscope 
it appears almost transparent except where food masses occur in the 
abdomen. A number of blackish hairs are found, on the legs, body, 
and especially at the end of the abdomen where some, here, attain an 
extraordinary length. In the plate these are curved so as not to take 
up unnecessary room. 
EXPLANATION oF Prare XXII. 
Fig. 1. Picobia villosa Hancock, ee greatly magnified, semi- 
transparent view. 
Fig. 2. Tarsus seen from the side ovine comb structures, the claws, 
and accessory stalked appendage (shown at a). 
Chicago. Josera L. Hancock. 
