DISCUSSION OF TABLE II. 



Of 91 species data are available;" but this is not much if we con- 

 sider that more than 2,000 species of Tabanidae have been described, 

 and 76 species have been recorded for the State of New Jersey alone. 

 Moreover, in a number of these 91 species from all parts of the 

 world, we have only very fragmentary data, as for instance in the 

 twelve species of Chrysops listed; of five of them we possess only 

 notes on their oviposition ; the whole life history of none of them has 

 been worked out. There are also comparatively few data on European 

 species.^^ 



From the list it is evident that the majority of Tabanidae of which 

 the life history is known, are aquatic in habitat: of 91 species noted, 

 65 are aquatic or probably so, 18 are terrestrial or probably so; of 8 

 species nothing definite can be said about their habits. The terres- 

 trial habit is then to be considered the exception. It is worthy of 

 note that all the known species of Chrysops are aquatic, in as far 

 as the eggs are deposited above water, or the larvae have been found 

 in the mud. The limit between an aquatic and terrestrial mode of 

 life is, of course, not always very sharp when the habitat is in fact 

 the soft mud at the border of ponds, brooks, and streams, as seems 

 to be usually the case, but most authors agree that the larvae live in 

 mud saturated with water, an environment which differs physio- 

 logically very little from water itself. I have therefore listed all 

 species as aquatic the larvae of which have been found in the mud 

 near water, or where the eggs are deposited above water. But there 

 is no doubt that some tabanids live in the larval condition at con- 



^^ Of two or three of the 91 species discussed here, we have in fact only in- 

 dications about their breeding habits, no actual knowledge of the stages, so in 

 Gasir oxides, Tabanus fuscipes, and Tabanus nigerrimus. Leaving these out, we 

 still have about 88 species on which some data are available. 



^^ Recently, I have obtained larval stages of 9 other North American species, 

 bringing the total number of species on which data are known close to 100. 

 These species are: Chrysops niger, obsoletus, univitlatus, Tabanus reinwardtii, 

 pumilus, orioii, two undetermined species of Tabanus, and one gemis incertum. 



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