Diptera: Nemocera vera, y. anovuda and Eremochaeta. 423 



IL Palpi one or Uvo-jointed, i)orrGct. (not pcndulous), the se- 

 cond jüint more or less clavate, larger than the first, which in 

 this case appears like a liaudle to the second; the joints of the 

 antennal flagellum, with rare exceptions, not homologous.i) 



All the other diptera. 



After having thus vindicated the rights of the Diptera Nemo- 

 cera Latreille, it remains for us to examine the Contents of this di- 

 vision, and to ascertain whether it is homogeneous or not. 



We soon perceive that some farailies in this division have, in 

 most cases, holoptic heads in the male sex, while in the rest of the 

 faniilies, which form the bulk of the division, such heads never occur. 

 After separating these two gronps of families we easily discover that 

 the larger one, whose males are never holoptic, is a very compact, 

 homogeneous group, connected by several other characters besides 

 that derived from the structure of the head. This large group (in 

 my „Suggestions") I called Nemocera vera. It contains the five 

 largest families of the Nemocera Latreille, which are rather evenly 

 distributed over the whole world: Cecidomyidae, MycetopMlidae, 

 Ctdicidae, Chiroyiomidae, and Tipididae. The Psychodidae form 

 a sixth, smaller family. The still problematic Dixa may count for 

 a seventh until further discoveries reveal its affinities. 



The residue of the Nemocera of Latreille consists of five small 

 families. very peculiar in their Organisation, but not showing any 

 distinct relationship to each other. They seem to represent the re- 

 mains of a more ancient fauna. I formed of them the artificial group: 

 Nemocera anomcda; the families which it contains are the Bibio- 

 iiidae, Shmdidac, BIepharoceridae,Bhyphidae. and OrphnepMlidae. 



The Nemocera vera represent a natural, compact group, bound 

 together by characters appearing in different parts of their Organi- 

 sation, as well as in their general aspect. They never have a holop- 

 tic head and hence, the differentiation of the sexes in the breadth 

 of the front, and the size and shape of the eyes, if it exists at all, 

 is reduced to a minimum. The eyes sometimes round or oval, but 

 most often lunate, are placed on the sides of the comparatively very 

 small head, and are separated by a more or less broad front; when 

 lunate, their Upper and lower ends are often approximate, but we 

 never meet in this group with that broad contact of the eyes which 

 constitutcs a holoptic head. The ocelli are gererally wanting, cxcept 



i) „Joints of the flagellum not homologous." I purposely use this, 

 merely negative, dcfinition, in Order to loave room for tho endless va- 

 riety in shape of tlie tliird Joint of the antennae of the Brachycera. 



