74 INSECUTOR INSCITI^ MENSTRUUS 



a basal and median collection of hairs. No lobes are formed, 

 nor is the location of the hair-tufts exactly that in which the 

 lobes later appear. We have here simply an indication. 



Group III. — Harpago well developed; side piece with a 

 basal lobe, small, not prominent, with a collection of long hairs ; 

 no apical lobe. 



This includes varipalpus, atropalpus, epactius, fluviatilis, 

 niger, taeniorhynclius, epinolus, sollicitans, mitchella, and nigro- 

 maculis and probably zoosophus D. & K. One of the species 

 lives in tree-holes, three in rock-holes, three in salt tidal pools, 

 and two in temporary ground puddles inland. Iti this series 

 we have the advance from breeding in the restricted water in 

 plant-tissues to the ground puddle, in which the species of the 

 highest groups so much rejoice. 



Group IV. — Harpago well developed, sometimes enormously; 

 basal lobe varying from a conical elevation with coarse hairs 

 to a flattened expanded membrane with short papillae and fine 

 setae ; apical lobe present, always conical, setose or bare. 



This includes the remaining species of Aedes, with the single 

 exception of canadensis, whose males are known, and prob- 

 ably the rest as well, somewhat over 60 species. All live in 

 temporary ground pools. Some of the species are of tropical 

 distribution, but the majority are boreal, breeding in the water 

 formed by the melting snow and having but a single annual 

 generation, overwintering in the &gg. One species is confined 

 to salt tidal pools and one invades this domain, though breed- 

 ing also in fresh water inland. The habit of being confined 

 to tree-holes or rock-holes is wholly lost. Moreover, not only 

 has this extension of breeding places been accomplished, but | 

 the primitive tropical distribution has been extended and even 

 the arctic regions invaded. 



Two subgroups appear, indicating an incipient dichotomy. 

 Four species have altered the structure of the basal lobe, 

 namely, impiger, diantaeus, pullatus, and aurifcr. The lobe is 

 large and conical, the hairs reduced to two, which have become 

 very stout and followed by a spine. Apparently this modifi- 

 cation did not prove a very happy one, for, in pullatus, the 



