THE STRAIGHT-SEAMED FLIES 



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preserved in the amber beds of the Baltic. Strata of the same age at Florissant, 

 Colorado, have also yielded fossil flies. A few have been obtained from Secondary 

 rocks. 



Mosquitoes 

 and Gnats 



THE STRAIGHT-SEAMED FLIES SUBORDER Orthorrhapha 



The first section of this suborder contains the gnats and mosquitoes {Culicidee), 

 daddy longlegs {Tipulidce} , true midges (Chironomidce) , and fungus midges (Myce- 

 tophilida). These families are sometimes spoken of collectively as the Nematocera, 

 or flies with thread-like antennae, on account of the length and thinness of those 

 organs, which usually consist of as many as ten or more segments. The maxillary 

 palpi also are elongate, and the body and limbs present, as a rule, the type with 

 which we are familiar in the gnats and daddy longlegs. 



The mosquitoes and gnats (Culiddce}, although often regarded as 

 distinct, are in reality identical. They abound in all lands, and may 

 be met with in cold barren countries like Iceland and Lapland as well 

 as in the dense forests of tropical climes, everywhere being the plague of travelers 

 on account of their insatiable thirst for blood and the intense irritation caused by 

 their bite. It is, however, only the females that bite and suck blood, and in this 

 connection it may be pointed out that 

 no members of the Diptera sting in 

 the sense in which the word is used 

 with regard to ants and wasps; that 

 is to say, the wound, although giving 

 rise to a sharp stinging sensation, is 

 inflicted by jaws, and not, as in the 

 case of the ants, by an organ especially 

 designed for the purpose placed at the 

 hinder extremity of the abdomen. 

 The annexed figure representing the 

 banded gnat (Culex annulatus), a 

 species sometimes found in houses, 

 and noticeable for being the largest 



British form, is selected to illustrate the mode of life characteristic of the members 

 of this family. The long slender eggs, amounting to some three hundred or more, 

 laid by the mother in batches on the surface of a pond or ditch, give rise to worm- 

 like larvae furnished with a distinct head, a large somewhat squared thorax, and a 

 tapering jointed abdomen. Along each side of the body there is a row of bristle 

 tufts, one for each segment, and the last segment is in addition produced into a 

 couple of tubular tails, at the extremity of which open the tracheae or breathing 

 tubes. Thus equipped, the young gnat hangs suspended in the water, its heavy 

 head directed downward, and the tip of its forked tail just projecting above the 

 surface, so that the apertures of its breathing apparatus are in communication with 

 the air. Occasionally when the surface of the water is disturbed, or from any 

 other reason causing alarm, the larva wriggles to the bottom of the pond, soon, 



BANDED GNAT. 

 a. Female; b. I<arva; c. Pupa. (All enlarged. 



