BIOLOGY OF PHILIPPINE CULICID.^. 253 



The piiinurtE are subcircular, their margins being excavated internally at the 

 base. They are devoid of cilia and are very minutely rugose or setose. The 

 urochaetffi are very short, being less than one-tenth the length of the pinnurse. 



The pupal stage lasts two to three days. 



Adult: Length, 4 to 5 millimeters. (PI. X, fig. 1.) The general color is light 

 brown. In perfectly fresh specimens three faint, darlj: brown, parallel longitudinal 

 lines are visible on the mesothorax, but in old specimens this is less apparent, 

 unless they are denuded. 



The hair-like scales of the mesothorax are golden in certain lights. In addition, 

 there are four well defined longitudinal rows of dark curved setae, two submedian 

 and two sublateral, on the mesothorax. 



The abdominal segments are clothed basally with flat, pale ochraeeous scales, 

 causing the appearance of transverse banding on the abdomen. 



The legs are uniformly dark brown and the proboscis, which is also dark brown, 

 is unhanded, thereby distinguishing this species from C. microannulatus Theob., 

 the only other mosquito with which it might at first sight be confounded, except 

 the occasional Mansonia uniformis Theob., which may be at once distinguished, 

 by the layman, by its brown and ochraeeous, banded legs. 



HABITS OF THE ADULT. 



This species is a domestic form par excellence, breeding only in or 

 near houses in the Philippines and causing more real annoyance than 

 any or all other species combined. It begins its attacks at nightfall, 

 and the pests may be seen as early as 6 o'clock, pouring into open 

 windows and doors in cohorts. Their humming can be heard con- 

 tinuously in a quiet room, especially if it is closed. Hardly a district 

 in Manila is free from these mosquitoes and they are found in all the 

 towns near the coast that I have visited. The style of architecture pre- 

 valent in Philippine towns, where the water tanks, reservoirs, bath-tubs, 

 cisterns, etc., are built in with the stnicture, and where, in later days, 

 these receptacles remain unused or superannuated, lends itself readily to 

 the harboring and breeding of Gulex fatigans, and I think it can be 

 stated that without doubt every house harbors and breeds its own supply 

 of these pests. Invariably, when I have been called upon to visit a 

 house especially plagued with 0. fatigans, I have found larvse actually 

 breeding in plain sight in sufficient numbers to supply two such dwell- 

 ing houses with adults. 



Being, as they are, purely domestic, these mosquitos are amenable 

 to such simple remedial or prophylactic measures as to render it surpris- 

 ing that people suffer themselves to be exposed to an annoyance and 

 menace to health which is so easily to be prevented. In every case a few 

 drops of petroleum placed on the surface of the water which may after- 

 ward be dra^vn from the bottom of the receptacle without danger of 

 taint, or the emptying of some unused vessel, will destroy thousands of 

 larvas and prevent the females from depositing their ova. It seems 



