Diptera: Nemocera vera, N. anomala and Eremochaeta. 435 



In some genera of Tipulidae, for instance in Megistocera, the 

 antennae of the female are very small in comparison not onlj" with 

 those of its male, but with the size of the insect in general. The 

 antennae of Amalopis and Pedicia are rather small in both sexes. 



The distinctive character of the antennae of the Nemocera (in 

 Latreille's sense) consists in the homology of the joints of the fla- 

 gelluni. In the Nemocera vera^ in most cases, the flagcllum counts 

 between 11 and 14 joints; these joints are cylindrical, elliplic, or 

 globular, and their juxtaposition produces the characteristic filiform 

 appearance of the anteuna. The basal, and one or several of the 

 terminal flagellar joints differ slightly from the others, without inter- 

 fering with the threadlike appearance of the whole. In the pectinate 

 antennae occuring in several genera of the Tipididae and Myceto- 

 philidae the homology of the majority of the intermediate joints of 

 the flagellum is likewise preserved. 



In this homology of the joints of the flagellum the Nemocera 

 (in the wider sense) differ from all the other Diptera, and the only 

 approach to this form of antennae I am aware of is found in the 

 family Xylopliagi [JLylophagus proper, Rhachicerus and perhaps 

 also the fossil amber-genera: Chrysothemis and Electra, the two 

 latter with 23 and 13-jointed antennae respectively). Some species 

 of the genus Subida also have antennae with almost homologous 

 flagellar joints. All these genera undoubtedly are very old forms in 

 the geological series. Their palpi however, two-jointed and generally 

 club-shaped, easily distinguish them from the Nemocera. 



Another distinctive character of the Nemocera vera consists in 

 the presence of what I have called the „sensitive hairs" on the 

 antennae. They are arranged symmetrically in both sexes, but are 

 especially conspicuous in male specimens, in the shape of verticils, 

 pencils and plumes. In some cases, they are shorter than usual and 

 difficult to discern among the general pubescence of the antennae 

 (for instance in the antennae oi Spaniocera, as represented in Win - 

 nertz, Cecidom. Tab. 4, f. 7, a. b.). 



The Mycetophilidae. alone have no sensitive hairs in the above- 

 described sense, except in the two genera Zygoneura^) and Epidapus. 

 I have already mentioned (p. 430) a New-Zealand PZa^?/wJ"« c/ which 



i) In my „ Characters of the larvae of Mycetophilidae (Proc. Ent. 

 Soc. Philad. 1862, republished by me in Heidelberg, 1886) I have de- 

 scribed (p. 18) the nn-tamorphosis of Sciara toxoneura O.S., vi'hich 

 later, in my Catal. N. Am. Dipt. 1878 I placed in the genus Zygonextra, 

 on account of its venation. Nevertheless, at is has no verticils on the 

 antennae, it is a transitional form and not a true Zygoneura. 



28* 



