MEGARHINUS TRINIDADENSIS 945 



or nearly so, with anterior cross-vein. Legs slender; vestiture dark metallic- 

 purple and violet; femora brassy beneath; front tibiae brassy on outer side; 

 middle tibiae bronzy on inner side; hind tibiae with scattered brassy scales on 

 outer side; middle tarsi with second segment silvery-white on outer side; hind 

 tarsi with fourth segment entirely clear white, fifth silvery-white along basal 

 two-thirds on outer side. Claw formula, 1.0-1.0-0.0. 



Length : 9 to 11 mm. 



Genitalia (plate 36, fig. 242) : Side-pieces over twice as long as wide, 

 strongly tapered to a narrow rounded tip; a conical basal lobe clothed with 

 coarse setae. Clasp-filament long and slender, about as long as side-piece, with 

 a long articulated terminal spine and a row of sparsely set setse within. Harpes 

 long, prominent, narrow, concave with revolute margins, tip bent outward and 

 pointed. Unci conical at base, tips produced as a pair of long, slender points, 

 dentose within. Basal appendages forming a rounded quadrate prominence 

 with a group of setae at each angle. 



Larva, Stage IV (plate 127, fig. 441). Head subquadrate, longer than wide, 

 sides nearly straight, insertion of antenna rather prominent ; front margin 

 deeply emarginate at middle, produced on each side of it into a large prominent 

 lobe. Antennae cylindrical, slender, rather long, smooth ; two separate hairs at 

 outer third followed by a short multiple tuft; three small terminal digits and 

 and a long seta. Two pairs of single hairs behind frontal lobes, a group of 

 three in the sinus behind the antennae, some small tufts beyond middle of sides. 

 Mouth-brushes inserted on frontal lobes, folded downward and backward. 

 Mental plate broadly triangular, an apical tooth in a shallow sinus ; nine stout 

 subequal teeth on each side, a second plate before, membranous, with stout 

 apical tooth and a row of many long fringed filaments on each side. Mandible 

 quadrangular, straight without, smooth ; two branched appendages at angle 

 before tip ; an outer row of coarse cilia ; terminal dentition of five teeth, very 

 large, ensiform, the third and fifth smaller; a large rounded projection basad 

 of the teeth, within which arises a row of long subequal setae. Maxilla rounded 

 quadrangular, the basal angle with a group of flattened appendages with re- 

 curved tips ; inner angle with shorter filaments, a seta and two papilla ; palpus 

 nearly divided by a suture, erect, columnar, flat at tip, smooth, with three rudi- 

 mentary terminal digits. Thorax rounded, about as wide as long ; lateral hairs 

 short, very stout, the heaviest ones spinulose. Abdomen stout, segments angled 

 at the sides, anterior ones shorter ; hairs abundant but not long, all the lateral 

 tufts multiple to fifth segment, double on sixth. Tracheal tubes invisible ; skin 

 darkly and blotchily pigmented. Air-tube short and stout, slightly more than 

 twice as long as wide, conically tapered outwardly; no pecten; a single tuft 

 near base. A large plate on sides of eighth segment, with two very stout ciliate 

 hairs on its posterior margin. Anal segment about as long as wide, ringed 

 by the plate ; dorsal tufts of two long brushes on each side ; a single spinulose 

 lateral hair ; ventral brush well developed, the tufts amply feathered ; anal gills 

 very short, bud-shaped. 



The larvae live in the water in holes in trees inhabited by other mosquito 

 larvae, upon which they prey. Mr. Urich and Mr. Busck both took them in such 

 locations. 



Island of Trinidad. 



San Juan (F. W. TJrich) ; Sangre Grande (F. W. Urich) ; St. Joseph, June 

 15, 1905 (A. Busck) ; Montserrat, June 27, 1905 (A. Busck). 



The specimens mentioned by Mr. Busck under this name (Smiths. Misc. 

 Colls., quart, iss., lii, 60, 1908) really belong to Megarhinus hypoptes. 



