AEDE8 EPACTIUS 643 



group of bristles. Postnotuin rounded, convex, brown, slightly pruinose, nude. 

 Pleurae and coxee clothed with patches of broad white scales and rows of pale 

 bristles ; pleurae brown, coxae luteous. 



Abdomen subcylindrical, flattened, tapering posteriorly, the cerci exserted; 

 dorsal vestiture of dull black scales, the segments with rather narrow, uniform, 

 white basal bands, present even on the last segment ; first segment with patches 

 of flat white scales and many pale setae; venter white scaled, a sprialding of 

 black ones at apices of segments, tendiag to form subapical bands, particularly 

 on distal segments. Cerci black. 



Wiags moderate, hyaline; petiole of second marginal cell shorter than its 

 cell, that of second posterior ceU also shorter than its cell; basal cross- vein 

 distant more than its own length from anterior cross-vein ; veins brown, scales 

 black except at base of costa, where they are silvery-white for a short distance ; 

 outstanding scales on outer half of wing linear, spatulate, black. Halteres 

 whitish. 



Legs rather long and slender; femora black, white-scaled at base and beneath, 

 apex broadly silver-white ; tibiae black-scaled, bases and apices white ; tarsi black, 

 hind ones with broad basal and apical white rings, the last joint entirely white; 

 fore tarsi without white rings; mid tarsi with the rings obsolete on last three 

 joints. Claw formula, 1.1-1.1-0.0. 



Length : Body about 3.5 mm. ; wing 3 mm. 



Male. — Palpi slender, straight, about three-fourths as long as the proboscis, 

 black-scaled; apex of long joint and last two joints with sparse, rather short 

 and coarse bristles. Antennae plumose, the last two joints long and slender, 

 rugose, pilose, black, the others short, pale, with brown rings at insertions of the 

 hair-whorls ; hairs of whorls long, dark brown. Coloration similar to the female, 

 the head entirely covered with sordid silvery scales, the black lateral spots being 

 absent. Abdomen elongate, the sides densely hairy, the segmental white bands 

 broader, the last segment entirely white scaled above. Wings narrower than in 

 the female, the stems of the fork-cells longer, the vestiture less abundant. Claw 

 formula, 2.1-3.1-0.0. 



Genitalia (plate 33, fig. 314) : Side-pieces over twice as long as wide, tips 

 tapered, bluntly rounded; apical lobe undeveloped; basal lobe rounded, sub- 

 spherical, setose. Clasp-filament long, slender, uniform, with a long terminal 

 spine. Harpes small, elliptical, concave, tips thickened and pointed outwardly. 

 Harpagones with a long, slender, curved stem and smooth terminal filament, 

 tapering to a point. Unci forming a basal cone with revolute margins. 



Lwrva, Stage IV (plate 119, fig. 411). — Head rounded, slightly widened 

 through eyes; antennae small, uniform, slightly spinose, with a small hair-tuft at 

 middle; upper pair of dorsal head-hairs double, lower pair single, ante-antennal 

 tufts in fours. Lateral comb of eighth segment of about twen^-five scales in an 

 irregular patch. Air-tube about Saree times as long as wide, slightly tapering 

 outwardly; peeten-teeth reaching to apical third, the outer ones stouter and sepa- 

 rated, extending beyond the hair-tuft. Anal segment longer than wide, with a 

 rather small dorsal plate, spinose posteriorly; dorsal tuft a long hair and tuft 

 on each side ; ventral brush well developed, scarcely exceeding barred area. Anal 

 gills longer than the segment, subequal, pointed. 



The larvae live in water in pot-holes or depressions in rocks. Mr. Knab got 

 them in depressions in bowlders in stream beds. At Cordoba they were asso- 

 ciated with Aedes fluviatilis and Culex pinarocampa. 



Southern Mexico. 



Almoloya, State of Oaxaca, July 30, 1905 (F. Knab) ; Cordoba, State of Vera 

 Cruz, January 4, 1908 (F. Knab) . 



