354 MOSQUITOES OF NORTH AIMERIOA 



Genitalia (plate 18, figs. 128 and 139) : Side-pieces over twice as long as wide, 

 tips rounded with a quadrate apical projection bearing a spine, three curved rods 

 with hooked tips, a leaf -like appendage and three setae; clasp-filament moderate, 

 slender with a terminal articulated spine. Harpes divided, inner branch bear- 

 ing large tuft of spines at tip, outer short and curved ; harpagones divided, one 

 branch forming a long, curved, spatulate process far exceeding spinose tips of 

 harpes. Unci obscured. Basal appendages, short, remote, setose. 



Larva, Stage IV (see the figure of the entire larva, plate 54) . — Head rounded, 

 widest through eyes, narrowed before, a notch at insertion of antennae, front 

 margin arcuate ; antennas rather large, spined on basal two-thirds, with a large 

 tuft from a notch, apex obliquely truncate and with three long setae, a short one 

 and a digit; both pairs of dorsal head-hairs and ante-antennal tufts multiple. 

 Mental plate triangular with a projecting central tooth and eleven on each side, 

 basal ones a little larger and more remote, last one small. Mandible quad- 

 rangular, with four filaments and a tuft of hairs before tip; an outer row of 

 cilia from a collar; a row of transverse prominences on outer margin bearing 

 hair-tufts; dentition of four teeth on a process, first longest; a spine before, a 

 small tooth and a large trifid one at base, a serrate filament and row of feathered 

 hairs within ; process below slightly curved, obscurely furcate, with a transverse 

 and longitudinal row of hairs and a tuft at tip of each limb ; basal angle large 

 with a row of stout hairs within ; a row of long hairs at base. Maxilla elongate, 

 conical without, divided by a suture ; inner half with a row of long spines along 

 margin, the basal ones feathered, three rows of cilia within, a row of long hairs 

 at tip, running down along the suture; outer half with two filaments near 

 middle, a few hairs below, a spine on other side and minute teeth on margin. 

 Palpus very small with four irregular apical digits, one of which is long. Thorax 

 rounded, wider than long. Abdomen moderate, anterior segments shorter; 

 lateral hairs multiple on first two segments, in twos on third to sixth ; subdorsal 

 hairs single on third and fourth segments; tracheae rather broad. Air-tube 

 rather stout, tapered on outer half, four times as long as wide ; peeten running 

 about one-third; single tooth broad with three to six branches; four tufts on 

 posterior margin, the subapical one moved laterally out of Kne. Lateral comb of 

 eighth segment of many spiues in a triangular patch ; single spine narrow, apex 

 rounded and fringed with spinules. Anal segment a little longer than wide, 

 ringed by the plate; dorsal tuft a group of three long hairs on each side; 

 a single lateral hair ; ventral brush well developed, confined to the barred area. 

 Anal gills rather short and broad, longer than the segment, tapered toward tips. 



Variety dipseticus Dyar & Knab. 



This race occurs in the arid region along the west coast of Mexico, from the 

 mouth of the Colorado River southward. The adults do not differ in markings 

 from the normal form, but the genitalia of the male differ in the much shorter 

 branch of the harpagones (plate 18, fig. 130), which does not extend like a 

 ribbon in the manner characteristic of typical quinquefasciatus. Our specimens 

 are from La Paz, Baja California, Mexico (A. Dug&s) ; Acapulco, Mexico, July 

 38, 1905 (F. Knab) ; Salina Cruz, Mexico (A. Dug^s) ; Salina Cruz, ]\rexico, 

 July 13, 1905 (P. Knab). 



Culex quinquefasciatus is widely distributed throughout the warmer portions 

 of the globe. It is distinctly a domestic species, and, while it does not show the 

 same degree of adaptation to man as A'edes calopus, it is clearly an associate of 

 man. It is very bloodthirsty and a source of great annoyance, not only by its 

 irritating bite, but as well by its song. It is strictly nocturnal and will bite in 

 complete darkness. It is probable that the female requires blood for the matura- 

 tion of her eggs. Undoubtedly the same female will suck blood repeatedly, mth 



