CULEX LATISQUAMA 305 



two setae, each from a deep insertion. Clasp-filament large, stout, slightly swollen 

 in middle, with an articulated subterminal claw. Harpes furcate, inner branch 

 short, smooth, outer long and slender, its tip bent at nearly right angles and 

 bearing a long row of teeth. Harpagones broad, twisted, furcated at outer third, 

 with a short inner and a longer outer branch with a recurved tip. Basal ap- 

 pendages short, remote, setose. 



Larva, Stage IV (see figure of the entire larva, plate 51) . — Head broad, quad- 

 rate, wider than long, hind angles squarely rounded, sides straight, a notch at 

 insertion of antennae, front broad, arcuate ; clypeus shallowly excavate centrally. 

 Antennae very long, stout, a large tuft at apical third, the portion beyond it 

 slender; basal two-thirds densely spined; three long hairs, a short hair, and 

 a digit at tip. Eyes large, pointed. Upper pair of dorsal head-tufts in fours, 

 lower single and very close to upper; ante-antennal tuft multiple. Mental 

 plate broadly triangular, a large central tooth and eight on each side, becom- 

 ing more pointed and more remotely spaced basally, seventh tooth larger than 

 the others', eight small. Mandible quadrangular, with four filaments from a 

 notch before the tip; an outer row of cilia from a large collar; a row of little 

 tufts from a prominence on the outer margin; dentition of four teeth on a 

 process, the first much the longest, a slender tooth before, a group of short irregu- 

 lar teeth at base, a broad filament and eight hairs within ; process below indis- 

 tinctly furcate, with groups of small hairs ; angle below small, but prominent, 

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

 conical, tip rather sharply tapered, divided by a band-shaped suture ; inner half 

 with a row of stout hairs on margin and a shorter row within; a row of long 

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

 the suture before the middle. Palpus small, somewhat tapered, with small 

 irregular terminal digits. Thorax angularly rounded, wider than long; hairs 

 very long, mostly single or double, but in tufts laterally on the meso- and meta- 

 thorax. Abdomen rather slender, anterior segments short, seventh segment dis- 

 tinctly elongate ; lateral hairs long on first two segments multiple on first, double 

 on second, short and double on third to fifth, very long and single on sixth. 

 Tracheal tubes narrowly band-shaped, slightly irregular. Air-tube very long 

 and slender, a little widened at base, else straight and uniform, about ten times 

 as long as wide ; pecten fine, reaching nearly one-third, the single teeth broad 

 with two or three stout branches ; no hairs. Lateral comb of eighth segment of 

 many spines in a triangular patch, those on anterior margin of patch small and 

 dense, posterior ones larger and longer ; single spine angularly elliptical, evenly 

 fringed with spinules. Anal segment as long as wide, ringed by the plate ; dorsal 

 tuft of two long hairs and a small brush on each side ; ventral brush well de- 

 veloped, moderately long, confined to the barred area. Anal gills small, not as 

 long as the segment, conically pointed. 



The larvse Kve in the water in the holes made by certain crabs along the sea- 

 shore. The adults frequent the upper parts of the holes. Mr. Knab observed 

 the adults to fiy out of the holes when frightened, but remain near and finally 

 return. They showed no inclination to bite or even alight upon the person. 

 The water in the holes was at a considerable distance below the surface and diffi- 

 cult to reach. 



Costa Eica and Panama. 



Port Limon, Costa Eica, September 25, 1905 (P. Knab) ; Caldera Island, 

 Porto Bello Bay, Panama, January 23, 1908 (A. H. Jennings). 



A new genus has been erected for this species, but upon characters of minor 

 importance, and we consider it not worthy of recognition. The larva described 

 above as belonging to this species has not been bred, but, as it was obtained from 

 the same crab-holes with the adults, the association is probably correct. 

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