486 GNATS OR MOSQUITOES — CHAPTEli XIV 



characterised by the possession of patches of scales of nearly circular 

 outline, showing no signs of striation except under high powers, 

 which bring out very close, transverse markings. These scales, in 

 almost all lights, are of a beautiful iridescent sky-blue, or occasion- 

 ally white, and give the insects a most distinctive appearance. 

 The palps in both sexes are quite rudimentary, consisting of 

 but one, or it may be, two short pieces ; but the proboscis is 

 proportionally, very large, being as long as, or longer than the 

 wing, the sheath broadened at the tip, and especially in the 

 S , fringed near the end on its margins with numerous strong 

 hairs. It may be distinguished from the other genera of the 

 yEdes group by the form of the fork-cells, which are very 

 short, with the anterior cell shorter than the posterior. Ila, 

 and IVa are continuous, without flexure to the apex of the wing, 

 while Up and IVp, are much curved. On casually examining 

 the wing, it looks much as if there were no extension of I beyond 

 the origin of II, but it really extends quite to the tip, though 

 almost bare of scales. The scales of the wing veins are lanceo- 

 late, with a graceful sigmoid curve. 



Arribalzaga founded his genus on two species, Pidcherrima and 

 Natalia, and pointed out that Osten-Sachen's ^des saphirinus 

 appeared to be of the same type, to which, of previously known 

 species, Mr. Theobald adds Walker's C. argijrojms, which, to- 

 gether with ten new species which have come to hand, brings 

 up the total to fourteen species. 



For the following rough notes on the larvae, which I repro- 

 duce in extenso, I am indebted to Dr. W. L. Forrest, of Antigua. 



"Found in ponds, covered with lennia-like weed, and other aquatic 

 plants. Colour, creamy-white ; dark brown head. Kot at all timid, 

 remains at surface at the same angle as Culex. 



" Head. — Dark brown, densely chitinous, smooth, heart-shaped, with 

 truncated apex, longer than broad, longer than thorax, as wide as 

 abdomen ; eyes sUghtly in front of widest part, with a row of bristles 

 pointing forwards ; antennae same colour as head, terminate with simple 

 spines, basal joint with a few bristles ; whorls close, pointing sideways, 

 extremities curving forwards, forming a straight line in front. On upper 

 surface, on either side of the median line, there is a single, stout, vertical 

 spine, one pair is posterior to the centre of head, and one pair anterior, 

 a little m front, and extending sliglitly towards lateral edge. There is 

 also a curved row of bristles behind the base of the antenme. 



" Thorax. — Much wider than long, translucent, surface studded with 

 colourless, cu'cular cells (warts or pits) ; frontid margin beset with long 

 compound bristles, not quite so long as head, pomting forwards ; meso- 

 thorax with similar bristles slightly longer, several rows confined more to 

 lateral regions ; near the uppermost bristle on each side, a slight 



