ANTENNA OF IMAGO 27 



times densely clothed with scales, as in Megarhinus and Aedeomyia. The shape 

 and proportion of the joints differs considerably in different genera. Thus in 

 Aedeomyia the joints are very short and stout, the second joint of the shaft 

 hardly longer than broad ; the succeeding ten joints are subequal, hardly twice 

 as long as thick. The opposite extreme is reached in Deinocerites, where the 

 joints of the shaft are slender and very long. 



In a majority of the species the antennae of the male are plumose ; that is, the 

 joints of the shaft are shortened, bringing the whorls of hairs close together, and 

 the whorls themselves are composed of longer and much more numerous hairs. 

 The torus, as already mentioned, is larger in the male, and this contrast is 

 greatest in the forms in which the male antennas are differentiated most. In the 

 typical plumose antenna the whorls of the first eleven segments of the shaft are 

 subapical, the basal one bearing a whorl as well as the others. The last two 

 joints are very long and slender and bear basal whorls of hairs. On all but the 

 last the slender segment is greatly expanded at the insertion of the whorl in 

 order to accommodate the numerous, closely crowded hairs ; the whorl does not 

 form a complete circle, but there is a very slight interruption on the outer side. 

 The first joint of the shaft is much longer than the succeeding ones and it bears 

 coarse hairs upon the part below the whorl. The short segments, aside from the 

 whorl, are smooth or nearly so ; sometimes very small hairs are present upon the 

 very short chitinous ring just above the whorl. The two last very long joints are 

 densely hairy beyond the whorl, the hairs of the penultimate joint are particu- 

 larly long and thus complete the plumose effect. The last joint is pointed at the 

 tip, its whorl contains fewer hairs and they are inserted as in the female. 



Raphael Blanchard, in Les Moustiques, pages 45 and 47, states that the 

 antenna of the female has fourteen joints, that of the male fifteen, following 

 Ficalbi in this respect. In fact, the number of segments is the same in both 

 sexes. Ficalbi's error occurs, as one can readily see by his figure, with the first 

 joint of the shaft of the male antenna ; the parts above and below the whorl are 

 regarded as separate segments. This was done, apparently, in the attempt to 

 homologize the antennre of the two sexes and, as the third antenna! joint of the 

 female bears no whorl, it was natural to consider the basal part of the same seg- 

 ment of the male as a unit, and the part beyond, with the whorl at its base, as 

 a separate segment. 



Many modifications occur in the different genera and species. In the male of 

 Megarhinus the antenna is remarkably stout and rigid; the first joint of the 

 shaft is unusually long and very stout, clothed with numerous coarse hairs and 

 a dense covering of scales ; the whorl is apical. In the succeeding ten joints the 

 whorls are much nearer base than apex, and the apical part of the joints is dis- 

 tinctly hairy. 



In Culex latisquama the antenna? of the male are remarkably long, nearly 

 equaling the considerably lengthened antennae of the female. They are of the 

 usual plumose plan but there is a lengthening of all the joints ; even the two 

 terminal joints are longer than in the ordinary type and the last joint is the 

 longest ; the ten shorter subequal joints are from three to four times as long as 



