798 N. C. AGR. EXP. STA. BUL. 239 
Holotype and two additional males and five females, San Pedro de Montes 
de Oca, Costa Rica,’ December, 1936 (C. H. Ballou) ‘“‘No. 417”; nine males 
and eight females, same data as preceding except date, February - May 1935; 
five females, same data as holotype except date, August 9, 1934, and host, 
‘“‘on coffee’; and one female, Las Cruces, near San Vito, Costa Rica, March 
19-20, 1965 (S. and W. D. Duckworth) (USNM). Five males, San José, Costa 
Rica (H. Schmidt); one male, Pacific side, Costa Rica (H. Schmidt) (ZIMH). 
N. rostris, n. sp., is closer, in the structure of the male genitalia, to N. scissa, 
n. sp., than to other species in the genus, but can be separated readily by the 
retrorse short branch of the ventral aedeagal process, and by the wider 
separation of the base of the shaft from the ventral process, both of which dif- 
fer in sctssa. 
Nielsonia scissa, NEW SPECIES 
FIGURE 644, PAGE 797 
Length of male 8.4-8.7 mm, of female 8.9 mm. Head with median length of 
crown varying from slightly more than six-tenths to slightly more than seven- 
tenths interocular width and from approximately four-tenths to slightly less 
than one-half transocular width. Male pygofer with posterior margin slightly 
convex below apex, dorsal process as in WN. rostris, n. sp.; connective as in 
rostris; aedeagus with shaft closely associated basally with base of ventral 
process which arises from ventral portion of atrium, extends posteriorly in its 
basal half, curves dorsad and tapers in its apical half, and bears a short acute 
smaller process near its midlength, as in rostris, but not retrorse, the longer 
process not close to the shaft in lateral view, shaft with curvature less than in 
rostris. 
Color as in WN. rostris, n. sp., but with two spots on crown before ocelli large, 
and face with black markings consisting of a variable area on clypeus, two 
spots at apex of clypellus, and lateral clypeal sutures. 
Holotype and one additional male and two females, Guayaquil, Ecuador; 
holotype 1941 (C. L. Fagan); other three specimens February 20, 1950 (S. W. 
Frost) (USNM). 
N. scissa, n. sp., is closer to WN. rostris than to other species in the genus, but 
differs in the form of the ventral aedeagal process and the smaller process it 
bears, as well as in the less arcuate form of the aedeagus. 
Nielsonia pretensa, NEW SPECIES 
FIGURE 645, PAGE 799 
Length of male 8.7-9.0 mm. Head with median length of crown varying 
from slightly less than two-thirds to approximately seven-tenths interocular 
width and from slightly more than four-tenths to slightly less than one-half 
transocular width. Male pygofer with posterior margin oblique and almost 
rectilinear below apex, with a short dorsal anteapical heavily sclerotized 
process directed posteromesally, not attaining apex of pygofer, and with a 
