38 [February, 



Hermetia in its Australian relative Massicyta*) ; 2. bisected eyes, 

 with larger facets above than below (in the male) are of very frequent 

 occurrence ; 3. eyes of variegated colour are more common in this 

 Section than in any other of the whole Order of Diptera, principally in 

 the Stratiomyidce and Tahanidce ; 4. the antenna; in the group Eremo- 

 chcBta are characterized by what I should call a morphological 

 restlessness ; there is no other group of Diptera m which the structure 

 of the antennas varies so much, even in closely related genera. These 

 various forms offer a complete transition from the thread-like antennae 

 with homologous flagellar joints, characterizing the Nemocera (such 

 antennae occur, for instance, in Suhula varia, and in Xyhphagus), to 

 the disc-and-arista type, which becomes so common in the other great 

 division, the Cyclorrhapha. This transition is effected by the joints 

 of the proximal portion of the flagellum tending to coalesce and to 

 form a compound joint in various shapes, while the joints of the distal 

 portion gradually pass into the form of a simple bristle. Portions of 

 the antennae are often beset with more or less long and dense hairs, 

 but the analogue of what I called sensitive hairs in the Nemocera, 

 forming a verticil, a pencil, or a plume, does not occur here. 5. There 

 are three well-developed puhuUi, which is one of the most characteristic 

 features of the Eremocha-ta ; exceptions are rare. The legs are 

 generally smooth, without those bristles and spines that distinguish 

 the Asilidce, and, in a lesser degree, the Bomhylidce and TherevidcB. 



For the final adjustment of the families of this group we must 

 wait for more material. The original arrangement was principally 

 based upon the common European forms ; but this section, perhaps 

 more than any other, is represented by very remarkable and often 

 anomalous forms in the other continents, especially in the tropics ; the 

 anomalous forms that disturbed the old arrangements came especially 

 from Chili {Coenura, Heterostomus^ , and recently from North America 

 {Agnotomyia, a Leptid, with only four posterior cells ; Arthroceras, 

 also a Leptid, but with the antennae of Coenomyia ; the singular genus 

 Olutops, &c.) ; about Australia and Africa we know almost nothing. 

 Certain it is that the very problematic family of Xylophagidce must be 

 given up, and its contents, temporarily at least, united with the 

 LeptidcB. Even the AcanthomeridcB may have the same fate ; apart 

 from their enormous size, they are not sufficiently distinguished from 

 the Leptidce, in the new composition of this family. 



* The genera Psammorycter, Lamproniyia, and Pheneus, forming the group Psummort/cterina, 

 Loew, have a narrow front in both sexes, and in this character, as in their whole appearance, 

 seem to mimic the Asilidce ; but here again their close relative, Triptotricha, has a holoptic head 

 in the male. 



