ANOPHELES ARGYRITARSIS 969 



Male. Palpi as long as proboscis, the last two joints thickened into a distinct 

 club and bearing long black hairs; chib dorsally white scaled, with a black 

 median ring and black at base ; a Avhite ring at middle of long joint. Antenna 

 densely plumose; last two joints long and slender, rugose, pilose, black, the 

 others short, white, with black expanded basal rings bearing long, dense, silky- 

 brown hairs; tori small. Coloration as in the female. Abdomen elongate, 

 slender, depressed, somewhat expanded towards apex. Wings narrower than 

 in the female; stems of fork-cells longer; vestiture somewhat sparser. Claw 

 formula, 2-0.0-0.0. 



Length : Body about 4 mm. ; wing 3.5 mm. 



Genitalia (plate 38, fig. 258) : Side-pieces over twice as long as wide, tips 

 rounded ; clasp-filament long and slender, broadly thickened at base and toward 

 apex, terminally with a short and spatulate articulated spine that arises a little 

 to one side of the pointed apex; two long approximated spines with recurved 

 tips below middle of side-piece, a similar smaller pair at base and a single stouter 

 one toward the outer aspect ; false harpes small, flattened, revolute ; unci forming 

 a stout process with small apical notch. 



Larva, Stage IV. Head elongate, rounded, bulging at the sides, antennae 

 laterally inserted, portion before antennte conically produced; both pairs of 

 dorsal head-hairs single but numerously branched, in a line between antennae, a 

 smaller hair at base of antennae ; two long approximate spines on clypeus. An- 

 tennas moderate, subcylindrical, slightly tapering outwardly, coarsely spined on 

 inner side; a small dendritic tuft at basal third; two long terminal spines, a 

 slender tuft exceeding the spines and a small digit. Mental plate small, with a 

 central tooth and four on each side ; first and second nearly equal, third remote, 

 fourth small. Mandible rounded quadrangular ; a row of filaments at base be- 

 coming smaller outwardly ; four filaments before tip, two smooth, two serrately 

 notched ; an outer row of cilia ; eight serrate filaments on outer margin ; dentition 

 of two small teeth, a large notched one on lower declivity, followed by two small 

 teeth and a long row of confluent spines ; two serrate filaments within ; basal 

 angle slender, rounded ; a row of long hairs at base. Maxilla transversely quad- 

 rangular, serrate along outer margin ; hairs short, longer at inner angle, below 

 which are two small filaments; palpus moderate, tapered outwardly, a large 

 dendritic tuft, a group of digits and flattened appendages at tip. Thorax sub- 

 quadrate, about as wide as long; hairs short, stout, amply feathered, also some 

 branched hairs, single hairs and tufts. Abdomen stout, anterior segments 

 shorter ; lateral hairs on first three segments long, feathered, double on first and 

 second, single on third ; hairs on succeeding segments small, smooth ; a dorsal 

 series of six pairs of fan-shaped tufts on the second to seventh segments (plate 

 130, fig. 459). Air-tube sessile, subquadrate, roundedly angled posteriorly. 

 Lateral plates of eighth segment posteriorly with a series of spines, five or 

 six very long ones separated from each other by two or three short irre.gular 

 intervening ones. Anal segment about as long as wide, with a small dorsal 

 plate ; dorsal brush a long branched hair and a short tuft on each side ; a single 

 long lateral hair below the plate; ventral brush well developed, of long branched 

 tufts ; anal gills moderate, about as long as anal segment, tapered, blunt. 



The larvae live in all sorts of ground-pools. Mr. Busck found them in rain 

 water in an old dump car, in a shaded pool and in a swampy pasture, Mr. ELnab 

 found them in pools in a stream-bed; Mr. Jennings found them in a spring, 

 a stream, the edges of a reservoir, and in water-filled hoof-prints in a road. 

 Goeldi states that the adults are nocturnal but Neiva states that they are cre- 

 puscular. Jennings, who made extended observations in the Panama region, 

 discusses the species as follows : 



" It is widely distributed over the Isthmus but its numbers are never very 



great in any locality and it is not very frequently found in buildings. By reason 



of these facts, it is far less important economically than Anopheles alhimanus 



and tarsimaculata. It is the only species of Isthmian Anopheles which breeds 



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