Order DIPTERA. 



This order contains the flies, always recognizable by having two wings 

 only, the secondaries being reduced to little knobs or halteres. The 

 head is separated from the thorax by a distinct, very narrow neck, and 

 the antennae are either quite long or very short, often aristate. The 

 mouth parts are formed for scraping or sucking, or both, and never for 

 chewing, in the adult stage. The larvae vary greatly, but are usually 

 either very slender and elongate, or maggot-like in form. The metamor- 

 phosis is complete, and the change from larva to adult is more radical 

 than in any other order. 



Since the publication of the previous list our knowledge of the "Dip- 

 tera" has increased vastly, and collectors are more numerous than ever 

 before. Mr. Charles W. Johnson, now Curator of the Boston Society of 

 Natural History, has again prepared the list as a whole, and has added 

 perhaps the greatest number of species to it. But in the "Cecidomyiidae" 

 Mr. William Beutenmuller has done this work, and while the list in that 

 family is still far from complete, it is a much better picture of our fauna 

 than was the previous one. In the "Culicidae" the list is probably almost 

 complete. In no other family have collections been so thorough and 

 systematic, and it is believed that few species will be added in future. 

 Mr. John A. Grossbeck, one of the assistants in the mosquito investiga- 

 tion, has written this part of the list. In the "Tabanidae" Mr. V. A. E. 

 Daecke has supplied the mss., and here again his persistent and careful 

 work, supplemented by that of Mr. Henry S. Harbeck, has left little to 

 be done. In addition to these gentlemen, Messrs. G. M. Greene and 

 Chas. T. Greene, of Philadelphia, have added many records, and nearly 

 all the contributors to the previous edition have helped along the work 

 on this. 



Mr. Johnson estimated that the 1,200 species listed in the last edition 

 were about two-thirds of the actual number to be found in the State. 

 As before, all records not otherwise specifically credited belong to Mr. 

 Johnson. 



Family TIPUUM. 



These are the "Crane-flies," which resemble exaggerated mosquitoes 

 in appearance, and derive the common name from their long, ungainly, 

 slender legs. The head is often prolonged into a sort of blunt snout 

 at the end of which are the prominent palpi, which are sometimes as 

 long as the antennae. 



The species are most common in low meadows or at the edges of 

 woodland, and their flight is as uncertain and awkward as their appear- 

 ance. It is difficult to preserve these insects, because the legs break off 

 at the least provocation, e\en when they are alive. 



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