MOSQUITOS OF THE PALAEARCTIC REGION. 



265 



The f(-)llowing may be considered representative species :- 

 Itnrope. 

 A nophcles plunibeus. 

 Theobaldia anmtlata. 

 T. glaphyroptera. 

 T. morsUans. 



Orthopodomyia pidchripalpis. 

 Taeniorhynchus rkJiiardii. 

 A edcs semicantans. 

 A. rusticus. 

 A. genicidatus. 



It is of special interest to note that none of the European species in this hst 

 are at present known from Asia. 



As might be anticipated, few, if any, of the purely southern species have any 

 clearly recognisable North American representatives, but some of them have wide 

 extensions of their range into the Ethiopian and Oriental regions. The most note- 

 worthy of such species are Theobaldia longiareolata and Cidex tipulijormis. 



In the more northerly parts of the region the dominant group is the subgenus 

 Ochlerotatus of Aedes ; the species of Anopheles which occur are all of the typical 

 subgenus. Eurther south Ochlerotatus rapidly disappears, and begins to be replaced 

 in part by species of Cnlex, and in part by other subgenera of Aedes, while the 

 Anophelines of the Myzomyia group become numerous. 



I have endeavoured in this paper to revise the generic classification of the Cui.icidae 

 on a sounder basis than has been used hitherto, by defining the genera primarily 

 on characters which have no relation to sex. In previous papers I have tried to 

 minimise the use of secondary sexual characters, as well as of the merely superficial 

 characters of the scales, but found myself in some cases compelled to fall back upon 

 these, or else on the male hypopygium. A closer study of the insects now enables 

 me to point out what appear to be constant and important distinctions between 

 most of the genera which are applicable equally to both sexes without being so 

 artificial as the scale characters have been proved to be. Eortunately no changes 

 are involved in our conception of the limits of the genera ; these had been already 

 soundly established by the study of the larvae, and the new characters adduced 

 only confirm most of the conclusions already arrived at by a study of the early stages. 

 Several of the new distinctions employed are to be found in the thoracic chaetotaxy, 

 and to explain these clearly I give explanatory figures of the pleural bristles in 

 Theobaldia annidata and A edes genicidatus. The most important bristles for taxonomic 

 purposes I find to be those occurring on the area in front of the prothoracic spiracle. 

 This area is almost entirely occupied by the proepimeron, but there is a small, more 

 or less triangular area immediately adjoining the spiracle which is separated from 

 the proepimeron by a well-marked" ridge. The bristles which are found on this small 

 area I speak of here as the spiracular bristles. When present they project backwards, 

 covering and protecting the spiracle. When the spiracular bristles are absent, 

 their function is often assumed by the proepimeral bristles, which are usually situated 

 in a row near the posterior margin of the proepimeron ; it will sometimes be necessary 

 to look closely in order to ascertain whether the bristles present are spiracular or 

 proepimeral, or perhaps both ; their position relatively to the above-mentioned ridge 

 is the deciding factor. The two groups are obviously not homologous. 



The other groups of bristles on the pleurae are apparently of less importance, and 

 are for the most part more hair-like. They are as follows •.—Pronotal, on the pro- 

 thoracic lobes. Prosternal, on the prosternal lobes ; a group which Christophers 

 considers important in the Anophelini, but which seems to be fairly constant through- 

 out the CuLiciNi. Post-spiracular, a distinct group of some importance situated 

 a little behind the prothoracic spiracle and below the margin of the mesonotum. 



