TROMOPTERA 473 



" from N.-Z. contain Thcrevae, and tho earliest Dipteron described (1775) 

 " from' these islands was T. hilincata Fab., collected by Sir J, Banks, 

 " companion of Capt. Cook. The greatest difference between the Thercvidae 

 " and the three above-mentioned normal families of Tromojjtera consists 

 " in their earlier stages ; however the great mobility of the larva of 

 " Thcreva in hunting for prey, favored by its serpentine shape and tough 

 " consistency, may be premonitory of the first, mobile stage of the larvae 

 " of the other groups. Besides the Tlicrrvidac, the Cyrtidac also seem to 

 " be comparatively frequent in N.-Z. Three species of Cyrtidac, represent- 

 " ing as many genera, have been brought from that country. One of them, 

 " Oncodes hrunncus, seems to be exceedingly common. Thus, of the four 

 " families of Diptera, composing the Superfamily Tromoptera, the Thercvidae 

 " and Cyrtidac seem to be much more common in N.-Z. than in Europe 

 " or in North America. The Bomhylidae, on the contrary, flourishing in 

 " the rest of the world, seem to be exceedingly rare in N.-Z. I have never 

 " seen a Bombylid (or still less a Nevicstrinid) from N".-Z. in any collection, 

 " and none have been mentioned, as far as I know, in literature, except the 

 " two species of Ncuria, in Schiner's No vara- work, quoted as coming from 

 " Auckland, N.-Z., but the origin of which still requires confirmation, as 

 " there is no other authority for the locality. One of these Ncuriae has 

 " been described by Macquart from Eastern Australia ; the locality of the 

 " other is vaguely described by Fabricius as ' the Islands of the Pacific 

 " Ocean.' Such a striking result, although based upon rather meagre 

 " data, has its significance, the more so as both Bomhylidae and Nemes- 

 " trinidae are very abundant in Australia. This result seems to me a 

 " potent argument for the opinion that the Thcrevidae are an ancestral 

 " form among the Tromoptera." 



" The Scenopinidae, according to the received opinion, may be placed 

 " alongside of the Thcrevidae, although they are glabrous and bristleless, 

 " while Therevac have a regular system of macrochaetae on the thorax." 



ARRANGEMENT. 



The natural sequence of families runs from tho Cyrtida: to the 

 Bomhylidm, probably through the bare humpbacked Glahellula, Platyijygus, 

 etc., on through the Bomhylince to the Lomatinm and AnthraeinK and 

 thence to the chsetophorous and five-posterior-celled Thcrcvidce, after which 

 embryonic characters may lead to the Scenopinidw, or else the stepping 

 stone would seem to be natural on to the Apioceridw (with which the 

 Mydaidoi must have some close affinity, as is proved by the venation) 

 and so on to the Asilijuc ; or else a connection may be traced from the 

 Philopotinm to the Toxop)horina: through the remarkable dorsal develop- 

 ment of the prothorax, but against that has to be placed the very strong 

 chsetotaxy of Toxophora ; in fact the position of the Toxophoi^inw and 

 Systropince is not clear. 



