REPORT OF THE STATE ENTOMOLOGIST I904 443 



characters presented in both larval and adult stages. Dry material 

 has value in this work, though better preparations can be obtained 

 from recently killed insects, and it has been our aim to rear, so far 

 as possible, all of our native species and thus obtain the clearest 

 possible idea of their characteristics in both adult and larval stages. 

 The following observations are made public at this time because 

 they should prove of considerable service to others engaged in 

 similar investigations, and particularly because they deal with a 

 comparatively unworked field. 



The material on which these studies are based, has been derived 

 from a number of sources. The most important contribution of 

 exotic forms was obtained through the kindness of Prof. F. V. 

 Theobald of England, a recognized authority on this group. Rep- 

 resentatives of additional species have also been received from Dr 

 Andrew Balfour of Khartum Egypt, Dr M. Grabham of Kingston 

 Jamaica, and of Philippine forms from C. S. Ludlow, Surgeon 

 General's Office, Washington. A large proportion of native 

 material has been obtained by collecting and rearing, though we are 

 deeply indebted to the kindness of Dr H. G. Dyar of Washington, 

 Dr J. B. Smith of New Jersey, Dr W. E. Britton of Connecticut, 

 Prof. Glenn W. Herrick of Mississippi, Prof. V. L. Kellogg of 

 California and H. J. Quayle, also of California, for adtilts or larvae 

 from different sections of the country. Special mention should also 

 be made of Mr J. Turner Brakeley of Hornerstown N. J., who very 

 kindly sent examples of several rare and extremely interesting 

 species. 



LARVAE 



The larvae of this group are of peculiar interest because most 

 repressive or exterminative work must be directed against them, 

 and the ability to recognize species in the immature stage is fre- 

 quently of the greatest value in determining the most satisfactory 

 method of treating a mosquito -breeding area. Environment is of 

 considerable value in determining mosquito larvae, since certain 

 species exhibit decided preferences in breeding places, some being 

 found only in or near brackish or salt water, others only in fresh 

 water, a few in foul water, some in warm, fresh water, while others 

 prefer cool spring-fed pools, tree holes or holes in rocks and other 

 diverse places. The larvae as a rule subsist on decaying vegetable 

 matter and algae, though certain species, notably Psorophora, 

 Gorethra, Eucorethra and Sayomyia are carnivorous, and the first 

 named in particular, is probably of considerable economic import- 

 ance, since these predaceous larvae imdoubtedly devour large 

 numbers of the smaller pestiferous mosquitos. 



