52 MOSQUITOES OF NORTH AMERICA 



plants. One is typified by W. mitcheUii, the adults possessing male genitalia 

 of that type, while the larvae agree with the type of that larva. The larvae do not 

 segregate further, but upon the genitalia three subgroups appear, namely, besides 

 the mitcheUii group, one typified by W. vanduzeei, and probably containing all 

 the species with silvery prothoracic lobes, the other typified by W. chrysomus. 

 To this last subgroup belongs the subboreal W. smithii inliabiting Sarracenia. 

 The third bromelia group is uniform in the larva, typified by W. circumcincta, 

 but shows two markedly different types of genitalia. The aberrant type is typi- 

 fied by W. trinidadensis, and probably includes all of the species with silvery 

 scutellum. The next distinct group consists of those species inhabiting Heli- 

 conia, Calathea, and Calladium, and perhaps other plants holding water in the 

 flower-bracts or leaf-axils. The group is typified by W. cacodela. The Calla- 

 dium species, inhabiting the leaf-axils, form almost a distinct group from the 

 flower-bract species, especially the larvae being entirely dissimilar. This sub- 

 group, or group, is typified by W. pandora. The last group is that inhabiting 

 tree-holes, bamboo-joints, etc. This may be typified by W. symmachus. The 

 larvae, as far as we know them, are uniform, but the genitalia indicate two sub- 

 groups, typified, besides the symmachus group, by W. hromeliarum. Finally, 

 there remains the group typified by W. aporonoma, with a unique type of geni- 

 talia, allied to those of the mitcheUii group, and with larvae indistinguishable 

 from that group, but living in cocoanut-husks, etc. We know so little of this 

 group that it is difficult to be sure of its proper position. It comprises, besides 

 apronoma, only hemisagnosta, of which we have no genitalia. 



Among the members of this large genus it is probable that considerable 

 diversity exists in habits and life histories, but of most of them we know 

 nothing. As to what fragments of information we do possess, however, they 

 indicate a general similarity with the one species which inhabits temperate 

 latitudes and is on that account better known. This species lives in the water 

 in the leaves of the pitcher-plant, which grows in swampy localities. The eggs 

 are deposited in the young leaves, singly, attached to the leaf-surface within 

 before any water has accumulated. They hatch after the leaf has been filled by 

 rain-water and the larvae grow slowly, feeding upon the insect remains and 

 other detritus that accumulate in the leaf. The larvae pass the winter frozen 

 up in the cores of ice that form in the leaves and finish their development in the 

 spring, when, after pupation, the adults emerge. This species is not known to 

 bite and the adults probably frequent the immediate vicinity of the marshes. 

 We have no observations on their habits, as the species is practically never seen 

 unless bred. In the case of the tropical species there is no necessity for a period 

 of hibernation, but the dry season, when the water disappears from the leaves, 

 is in all probability passed in the eg^ state. It may, of course, be passed in the 

 adult state; we have no definite information on the matter, but the former 

 seems to us the more probable. In two cases Mr. Busck has found the eggs in 

 numbers in the newly opened flower-spathes of Heliconia, where as yet no water 

 was present. Some of the tropical species inhabit the water between the leaves 

 of Bromeliacese, others in other plants carrying water in the leaves, such as 

 Calladium, etc., or in flowers, in some of which the liquid is apparently largely 

 secreted by the plant itself {Heliconia, Calathea) ; others in water in hollow 

 trees, bamboo-joints, cocoanut-husks, etc. The species are difl'erent in the case 

 of the several plants that have different characteristics, while the tree-hole 

 species form another group. No species inhabit open water or earth pools. The 

 development is usually rather slow, and even the pupal period is rather long. 

 Many, if not all, of the tropical species as adults are diurnal in habit and the 

 females, at least of some of the species, will suck blood. They inhabit forested 

 regions, where their breeding-places occur. 



