64 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
in length to tibia. Middle coxa with a single row of bristles; femur 
with short inconspicuous 'comb.' Submesotibial bristle absent. 
Anterior coxa with two rows of bristles. 
Chactotaxy. — Anterior dorsocentrals considerably longer than ves- 
titure of prescutum and as long as or longer than anterior postsuturals; 
inner presuturals, weak if at all distinguishable. Four pairs posterior 
dorsocentrals, last two longest; prescutellar acrostichals present; 
three sternopleurals. 
Abdomen. — Lamellae of fourth ventral plate without ' brushes ' 
and widely separated by a U-shaped space; in profile posterior end of 
inner margins seen turned downward and bearing short hairs. 
Chaciotaxy. — Second segment with complete marginal row of short 
bristle-like hairs; third with corresponding row of slender bristles, 
the two central ones generally the strongest, fourth with complete row 
of bristles ending ventrally at forward turn of margin. 
Genital segments. — First, generally gray pollinose, except 
'humps' which are darkened, rarely same color as second; vestiture 
of short scattered bristles ; outline in profile somewhat convex ; second 
dull orange. Forceps prongs approximated basally for at least half 
their length, their tips parallel, not convergent. 
Genitalia. — Posterior plate of penis not knobbed at tip, but pro- 
longed forward laterally as two short arms; median process about as 
broad as penis, bluntly bilobed at end, extending farther forward than 
laterals, and practically completely chitinized ; lateral processes entirely 
chitinized, blackish and quite small, occupying only a small part of 
space between median process and the short arms of posterior plate. 
Described from six specimens; fourteen others have also been 
examined. 
Range. — New England: Mass.: Amherst, Forest Hills; Me.: 
Casco Bay; Conn.: New Haven, Middletown, Branford. 
United States: N. Y., N. J., Pa., 111. 
Foreign: Canada. 
The name of this species was suggested by the presence of the 
lateral vertical bristles. Apparently it is a northern species and 
probably extends west at least as far as the Rocky Mountains. 
The best characters for separating it from R. quadrisetosa (Coquil- 
lett) are the presence of lateral vertical bristles and the parallel prongs 
of the forceps. The former character can always be used if one is 
