LUTZIA ALLOSTIGMA 473 



ments transverse ; lateral hairs of first two segments multiple, double on third 

 and fourth, single and very fine on fifth. Air-tube stout, conically tapered 

 outwardly, about four times as long as wide, the surface finely spicular ; pecten 

 reaching slightly beyond middle of tube, of a series of about twelve slender 

 teeth, the last ones well separated; single tooth a simple spine with excavate 

 base; a partly double row of moderately long multiple hair-tufts posteriorly, 

 from base almost to apex of tube ; a black band around base of tube. Lateral 

 comb of eighth segment of many spines in a triangular patch; single spine 

 elliptical, often broader without, fringed with long spinules. Anal segment 

 longer than wide, obliquely excised below; dorsal hairs two on each side; a 

 single lateral hair ; ventral brush well developed, the barred area reaching half- 

 way to base. Anal gills very small, slender, in a small group distally on the 

 segment. 



Type. no. 14501, U. S. National Museum. 



The larvffi are predaceous upon the larvae of other mosquitoes, principally of 

 the genus Culex. Mr. Jennings has observed the eggs; the following is his 

 account of them and the larvse : 



" On May 30, 1908, while collecting along a rapid mountain stream on the 

 Island of Caldera, Porto Bello Bay, Rep. Panama, I secured several masses of 

 mosquito eggs, which subsequently proved to be those of Lutzia Bigotii. 



" They were taken from a small pool in the rocky bank of the stream, the water 

 of which was supplied by the stream itself, the pool being nearly filled with 

 vegetable matter consisting of dead leaves, twigs, petals of flowers, seeds, etc. 



" !N"early full-grown larvas of Lutzia were present, as well as many of Anoph- 

 eles eiseni and many of several species of Culex, none of the latter, however, 

 being bred. 



" The eggs were cylindrical, about one thirty-second of an inch in length, as 

 nearly as could be estimated (no means of accurate measurement being at 

 hand), slender, and terminated in a nearly hemispherical head of the same 

 diameter as the body of the egg, which, however, was drawn to a low point or 

 apex. The body of the rod-like egg was of a pale yellowish-white, with a metallic 

 reflection appearing almost golden in certain lights, while the apex or head, 

 which was sharply defined, was of a pale blue colour. 



"The eggs were arranged in a double row, forming a raft or boat. The 

 largest mass contained twenty-five pairs, but with nothing to indicate its original 

 size. Several smaller masses were taken from the same pool, but whether they 

 had formed a part of the same or another raft it is impossible to say. 



" The eggs adhered to each other rather tenaciously, and did not become 

 separated by being poured into a collecting vial nor by the rather rough journey 

 back to camp. 



" The * boat ' floats low in the water, the rod-like portion being nearly sub- 

 merged, only the * head ' showing above the surface. 



" I should think that these eggs were laid during the night of May 28th. 



" At 8 p. m. on May 30th, or presumably 48 hours after being laid, hatching 

 began, the young being easily identified, and showing the characteristic attitude 

 and habits of the larva of this species. They immediately began preying vora- 

 ciously upon each other, and materially reduced their numbers before the next 

 morning, when they were separated. 



" In hatching the young larvae emerged from the bottom of the egg, the clear 

 yellowish-white colour becoming dark and blackish and the cohesion of the 

 empty cases being lost, the eggs fell gradually apart and the mass finally dis- 

 integrated. 



" The young larvae were carefully separated and grew rapidly, increasing by 

 the next morning fully 50 per cent, in length and doubling their size within 24 



