BIOLOGY OP PHILIPPINE CULICID^. 251 



This mosquito is by far the commonest species to be encountered in 

 coast towns in the Philippines. It is a night flier, never attacking before 

 5 o'clock in the afternoon and seldom biting after 13 midnight. 



Egg: The eggs of Gulex fatigaiis are laid in concave rafts which float upon 

 the surface of the water. (PI. VII, fig. 1.) These rafts are usually about three 

 times as long as they are broad and contain from 180 to 350 eggs, usually in 

 six to eight rows varying in length, as will be seen on Plate IX. These diagrams 

 represent the shapes of 18 egg-masses laid in a jar of rain water in the Ento- 

 mological Laboratory during the night of September IS, 1907. 



Length, 0.70 millimeters; of a dark gray, somewhat iridescent. The egg has 

 a detachable, cup-shaped operculum at the base (PI. VIII, fig. 2), which opens 

 back when the larva emerges, but which is frequently not entirely detached from 

 the remainder of the egg-shell. In the center of the operculum is a tiny pro- 

 tuberance or spine which, in each egg, passes downward through a small hole 

 in the center of a veiy small circular fringe. This fringe is composed of radiating, 

 elastic filaments which, when the egg touches the water, spread out in the form 

 of an inverted saucer and support the egg in an upright position (PI. VIII, 

 fig. 2 ) . It has been found by experiment that a single egg, if carefully placed 

 upon the surface film with the tips of the fringe touching the water, will retain 

 its vertical position. As the eggs are deposited they touch each other along 

 their sides, and, owing to the upper end being less than the lower in diameter, 

 the final result is a concave raft of eggs, eacli standing upright and being slightly 

 glued to its neighbor. When the egg leaves the ovipositor of the female, which 

 it does large end first, the extremities of the fringed cap are drawn together 

 so that the cap has the appearance of a tiny sphere adhering to the end of 

 the egg. Upon touching water this expands as before mentioned. 



Larva: The very young larvae are pure white and very active. In hatching 

 they increase their length about twice, so that they measure 1.5 to 1.6 milli- 

 meters when they emerge. Length of full-grown larva, 7.5 to 8 millimeters. 

 (PI. VIII, fig. 3.) It is dark gray, the ej'C-spots being nearly black. The head 

 is subspheroid, being slightly subtriangular anteriorly. The antenniE are one- 

 half as long as the head, slightly curved. The first segment is spinous on the 

 outer convex surface and around its entire basal area. At a point two-thirds 

 the distance from the base is a small tubercular shoulder or notch upon which 

 grows a cluster of about 24 to 26 pectinate setse, each one of which is more 

 than one-half of the length of the entire antennae. 



These setae, in living specimens, are spread out in the form of a fan (PI. 

 VIII, fig. 4), but may be closed up voluntarily by the insect when it is not 

 feeding. Four simple bristles project from the apex of the first segment, located 

 two on either side of the base of the second segment. 



Six groups of pectinate bristles are found across the frontal area, one at 

 the base of each antenna containing twelve branches and four submedian of 

 six and eight branches, those with eight being nearer the median line. 



Mediad to each eye-spot is a simple and a trifid seta. 



A row of simple, bifid and trifid bristles extends across the anterior area of 

 the thorax. 



Slightly dorsad to each of the middle pseudopoda is a minute, plumose bristle. 

 Tlie posterior pseudopoda are well developed. Dorsad to these are numerous 

 pectinate bristles in a single cluster on a slight tubercle, while the fore, mid 

 and posterior pseudopoda are provided with clusters of long, pectinate setae. 



Lateral, pectinate bristles grow from the first and fourth abdominal segments, 

 two or three on each tubercle, tliose on the first and second segments curving 



