338 GNATS OR MOSQUITOES — CHAPTER XIII 



a distinct metallic lustre. Thorax, including scutellum, clothed 

 with short falciform scales. Head generally as in Culex, but with 

 the nan-ow curved scales of that genus replaced by broader ones 

 exactly like those of the thorax. 



Wing scales much as in Culex. Fore ungues with an addi- 

 tional tooth in both sexes, those of the $ being large and stout. 



Arribillzaga gives as characters, which are found to hold good 

 in all the members of the genus with which we are so far 

 acquainted, the following : — Palpi of ? short, with the fourth 

 joint subconical, and the fifth oblong and longer and thicker than 

 the fourth. Those of the S . muoh as in his Taniorhynchus, but 

 thinner and less hirsute, obviously longer than the proboscis 

 and somewhat swollen towards the apex, the first and second 

 joints minute ; the third very long, nearly three-fourths the length 

 of the proboscis ; fourth and fifth subequal and together a little 

 shorter than the third ; the fifth oblong and tapering. 



He adds that the branches of the anterior fork cell are twice 

 as long as the fork stem, but this is not literally the case even 

 in the type species, /. cliscrucians, and certainly does not hold 

 good with all, though the stem is always much shorter than the 

 cell. 



All show a more or less distinct, nude inward extension of 

 III. beyond the transverse veins, a character which they share 

 with Armigeres, and, it may be added, with certain members of 

 most other genera. To that genus, indeed, they present a strong 

 general resemblance, especially in coloration, but the scales of 

 the head differ, being arranged as in Stegomyia, in Armigeres, 

 which wants also the metallic lustre of Janthinosoma. 



In all but /. oblita (Arribal.), which I have not seen, as nothing 

 resembling it has made its appearance at the British Museum, 

 and the description of which reads more like that of Q,n Armigeres, 

 all have a portion of the hind tarsi alone pale, and the extent 

 and position of this is alone sufficient to distinguish between the 

 six species with which we are at present acquainted. 



All appear to be sylvan insects, and one or two are said to 

 be very vicious and troublesome. 



Table of Species of Janthinosoma. 



A. With some portion of the hind tarsi white. 

 a. With the thorax decorated. 



)8. With the last two hind tarsal joints all white and a little of apex 

 of next. 



