30 The Mosquitoes or Culicidae of Jamaica. 



uniserrated ; in the mid the larger claw has one small tooth, and 

 the smaller is simple ; hind ungues equal and simple. 



Length. 5 5 mm. 



Geographical distribution. Southern States of North America 

 and Jamaica. 



Life-history and habits. This very distinct species is apparently 

 not common in Jamaica ; the specimens sent me were taken in 

 December and bred from larvae caught along the Spanish Town 

 Road, Kingston. 



The life-history has been worked out by Professor Gr. W. 

 Herrick.* He first noticed the larvae in an open sewage drain 

 at the College Campus of the Agricultural College, Mississippi, in 

 1901, and again scores in a roadside pool near Stark ville. At 

 first sight they might be mistaken for Anopheles owing to their 

 horizontal position in the water. They lie just below the surface 

 film. Rain-water pools of transient nature seem their favourite 

 abode, those found in the sewage ditch being exceptional. 



When the larva rises to the surface it assumes at first the 

 position of a Culex, but after a moment, if left undisturbed, the 

 body with a slight jerk floats quickly to an approximately 

 horizontal position, with the head on a level with the surface of 

 the water. It differs from Anopheles in this respect, however, 

 like a piece of slack rope, curved down between the head and 

 respiratory tube. The tube projects at least a third of its length 

 out of the water. They are constantly swimming about in a 

 backward direction. The anal filaments are much longer and more 

 slender than in Culex. Professor Her rick says the respiratory 

 tube is much longer than in Culex fatigans. The figure does not 

 show this, and a character of this genus is the short larval siphon. 

 The antennae have a small lateral tuft towards the apex. The 

 comb on the eighth segment is composed of conspicuously 

 toothed spines joined on a weak basal segment. The pupae are 

 large and are figured with long siphons, with two tiers at the 

 truncated end. This stage lasts, according to Professor Herrick, 

 forty-eight hours. The eggs are laid singly, as observed by 

 Dr. Grabham, and are possibly, as in G. sollicitans, laid on dry 

 mud or moist soil, and await the coming of rain. The eggs of 

 G. dorsalis can withstand desiccation some months, and hatch 

 out at once when placed in water. This habit of laying eggs on 

 dry or drying mud in places likely to catch water and so form pools 

 is apparently common to the members of this very distinct genus. 

 * Entomological News, p. 81, March, 1904. 



