TABLE OF FAMILIES. 



i. Flies of a leathery or horny structure, living parasitically upon 

 warm-blooded vertebrates in the adult condition, the larvae born 

 when nearly ready to pupate; often wingless or with vestigial 

 wings. .......... 65 



Flies of a softer structure, not ectoparasites upon warm-blooded 

 vertebrates, rarely viviparous. ...... 2 



2. Anal cell rarely narrowed in the border of the wing; antennae usu- 



ally composed of from eight to sixteen joints and more or 

 less freely articulated with each other, usually longer than the 

 thorax; not with a differentiated style or bristle;* palpi as a 

 rule with four or five joints; discal cell usually absent. . 3 

 Anal cell, if present, closed, or much narrowed in the border of the 

 wing; discal cell almost always present; palpi never with more 

 than two joints; antennae usually composed of three joints with 

 a differentiated style or bristle. 14 



ORTHORRHAPHA. 



A. NEMOCERA. 



Anal cell rarely {some Bibionidcr, etc.) narrowed in the margin, 

 if present; discal cell present only in many Tipulidce and the Rhy- 

 phidcz; second longitudinal vein often furcate, the third very rarely 

 if ever; palpi usually more or less elongate, composed of from one to 

 five, usually four joints, rarely absent; antenna usually elongate 

 a nd verticillate, generally filiform , rarely pectinate, composed of from 

 six to thirty-nine joints, usually from eight to sixteen, the joints oj 

 the flagellum homomorphic and usually freely articulated rvith each 

 other, a style or arista very rarely differentiated '.* For the most 

 part slender, delicate flies. 



3. Mesonotum with a complete, V-shaped suture (incompletely V- 



shaped and sinuous in the Ptychopterinae) . Wings many-veined, 

 often with a complete di>cal cell; ocelli very rarely present; 

 both sexes dichoptic. For the most part large, always slender, 

 flies with long legs; never very small. Daddy-longlegs, craneflies. 



Tipulidse, 81. 



* Chionea, a wingless tipulid, has the third antennal joint ending in 

 a slender, three-jointed style; the flagellum of the Orphnephilidae is 

 aristiform. 



(8) 65 



