272 F. W. EDWARDS. 



mosquito larvae have a number of predaceous enemies living with them. Possibly 

 this may help to explain the development of hairs on the soft parts of the body, 

 though their reduction on the head is not so easy to account for. The development 

 of additional chitinous plates may be merely a chemico-physical reaction to the excess 

 of tannin in the water. 



"Whatever may be the use of these larval modiiications, it seems certain that they 

 are due to environmental conditions (since they are shown by species in totally 

 unrelated genera), and therefore the genus Coelodiazesis, founded solely on these 

 characters, cannot be satisfactorily maintained. 



Distrihnlion. — Throughout Europe, wherever there are many deciduous trees, 

 in which rot-holes can form. Not yet recorded with certainty from North Africa 

 or Asia, except one from Katmia, Cilicia {Li. -Col. Lelean, recorded by Christophers). 



The Himalayan species A . barianensis, James, has been referred to by Christophers 

 as identical with A. plumbeus, but there are small differences : in A. barianensis 

 the white scales on the mesonotum extend further (almost half-way from the front) 

 and the femora and tibiae are conspicuously white at the tips, whereas in A . plumbeus 

 they have scarcely a trace of white. As there are also small distinctions between the 

 larvae, it will probably be best to regard the two as distinct species, occupying 

 separate geographical areas in the Palaearctic and Oriental regions. The type has 

 also a North American representative in A. barberi, Coq., M'hich is distinct from both 

 the old-world forms, though closely resembling them. 



4. Anopheles (Anopheles) macullpennis, Mg. (fig. 2, d). 



Anopheles maculipennis, Meigen, Syst. Beschr. i, p. 11 (1818). 

 Culex daviger, Fabricius [nee Meigen), Syst. Antl. p. 35 (1805). 

 Anopheles occidentalis, Dyar & Knab, Proc. Biol. Soc. Wash, xix, p. 159 (1906) ; 



Howard, Dyar & Knab, Mosq. N. & C. Amer. iv, p. 1026 (1917). 

 Anopheles lewisi, Ludlow, Psyche, xxvii, p. 74 (1920). 

 Anopheles selengensis, Ludlow, Psyche, xxvii, p. 77 (1920). 



This could not easily be confused with any other Palaearctic species except 

 A . elntus ; from this it differs in several small details of coloration, as indicated 

 in the key. Tne pale area in the fringe at the tip of the wing is diagnostic of A. 

 ma(yidipennis, when it is present, but can only be seen in perfect specimens, the fringe 

 at the wing tip being very easily denuded ; moreover, the fringe is entirely dark in 

 some individuals, and as the wing-spots also vary somewhat in intensity, the distinction 

 between the adults of these two species is not very clearly marked. Perhaps the 

 best distinction between the two species is in the colour of the scutum, that of 

 A. maculipennis having a broad brown or blackish-brown stripe on each side, as in 

 A. bifurcatus and A. plumbeus. 



According to Wesenberg-Lund the Southern European race of A. maculipennis 

 is smaller than the Northern. The difference, if it exists, is very slight, and is only 

 to be found in the average measurement, since many Mediterranean specimens which 

 I have seen are quite large. Dyar (in correspondence) also maintains that there is 

 a minute difference in the hypopygia between specimens from France and Siberia 

 and those from Hungary. I am unable to confirm this, and consider that the small 

 amount of variation which does occur is individual only. Mounts of male hypopygia 

 of specimens from Britain, Macedonia and Constantinople show no difference whatever. 



In my opinion the Western North American A . occidentalis is specifically identical 

 with A. maculipennis. I can discern no difference in the larvae ; the adults are 

 alike in all external features, and the only demonstrable difference in the male 

 hypopygia is that the two outer spines on the claspette are both pointed in 

 A. occidentalis, while one or both of them are blunt-ended in A. maculipennis. 

 Such a distinction seems to me inadequate even for varietal separation. The egg of 

 A . occidentalis is as yet undescribed, and may differ from that of A . maculipennis, but 



