CLASSIFICATION 455 



tion with the imago is the existence of a suture over the insertion 

 of the antennae in a portion, hut not all, of the Cyclorrhapha.^ 

 The next set of divisions used hy Brauer divides the Order into 

 four sections, viz. 1. Orthorrhapha Nematocera, 2. 0. Brachycera, 

 3. Cyclorrhapha Aschiza, 4. C. Schizophora. As these four 

 groups are recognised more readily than the two major groups 

 the student will do well at first to disregard the primary division 

 and consider the Diptera as divisible into four great groups. To 

 these four divisions we, however, add temporarily a fifth, viz. 

 Pupipara. This is included by Brauer in Schizophora, but it 

 appears to be really an unnatural complex, and had better be 

 kept separate till it has been entirely reconsidered. These 

 great sections may be thus summarised :— 



Series 1. Orthorrhcqjha Nemocera. — Antennae with more than 6 segments, 

 not terminated by an arista ; with tlie segments of the iiagellum 

 more or less similar to one another. Palpi slender and flexible, 

 four- or five-jointed.2 



Series 2. Orthorrhapha Brachycera. — Antennae variable, but never truly 

 Nemocerous nor like those of Cyclori-hapha ; Avhen an arista is 

 present it is usually placed terminally, not superiorly ; when an 

 arista is not present the flagellum terminates as an appendage 

 consisting of a variable number of indistinctly sej)arated segments ; 

 thus the flagellum is not comjDosed of similar joints ; [rarely are the 

 antennae as many as seven-jointed]. Palpi only one- or two- 

 jointed.2 Around the insertion of the antennae there is no definite 

 arched suture enclosing a small dejiressed space. The nervuration 

 of the wings is usually more complex than in any of the other 

 divisions. 



Series 3. Cyclorrhapha Aschiza. Antennae composed of not more than three 

 joints and an arista ; the latter is not terminal. Front of head 

 without definite arched suture over the antennae, but frequently 

 Avith a minute area of difterent colour or texture there. This group 

 consists of the great family Syrphidae, and of four small families, 

 viz. Conopidae, Pipunculidae, Phoridae, and Platypezidae. The 

 section is supposed to be justified by its being Cyclorrhaphous in 

 pupation, and by the members not possessing a ptilinum (or having 

 no trace of one when quite mature). The Syrphidae are doulitless 



^ Becher, TVien. Ent. Zeit. i. 1882, p. 49 ; for observation on connecting forms 

 see Brauer, Verh. Ges. TFien, xl. 1890, p, 272. 



^ The palpi are said to be of only one segment in some genera of Cecidomyiidae. 

 The Cecidomyiidae are easily distinguished by the minute size — body not more 

 than a line long — and by there not being more than six nervules at the periphery 

 of the wing. Aedes (Culicidae) has also short palpi. 



^ It is said by Schiner that in the anomalous genus Nemestrina the palpi are 

 of three segments. 



