BRITISH FLIES 33 



II. — Characters of the Larv.e of Orthorrhapha Brachycera. 



Translated from Denkschriften der mathematiscli-naturmssenschaftlichen Classe 



der Kaiserlichen Akademie der Wissenschaften, vol. xlvii. (1883) : 



I. Suborder: Orthorrhapha. 



Larva with a mouth- or jaw-capsule or with a well-differentiated head. Nymph 

 free or enclosed in the larval skin. In either case the larval skin bursts open {i.e., 

 in the first case at the time of pupation of the larva, in the latter case only when 

 the fly first emerges together with the inclosed nymph-skin) through a straight longi- 

 tudinal dorsal rent on the front end of the body and a rectangularly transverse rent 

 in front, in the form of a T-shaped slit, or sometimes through a transverse rent 

 between the eighth and ninth abdominal segments, and then on a place not previ- 

 ously indicated liy a seam (only in some Cecidomyidce). The wings of the fly develop 

 at the same time as the emergence from the nymph-skin. Nervous-system very 

 diverse, the thirteen ganglia either all separate or united into two or more complexes. 

 In the early state there are always two head-, three thoracic-, and eight abdominal- 

 ganglia present. 



The imagines are without the lunula above the antenna^ and the arched seam 

 above it, and also the ptilinum. 



Characters of the Main Groups. 



Sectio ]. Orthorrhapha nematocera.— Larva with opposing biting mouth- 

 parts, i.e., with horizontally moving raandildes ; or the mouth-parts entirely rudi- 

 mentary, but then the larva" is peripneustic with thirteen segments. 



8ectio 2. Orthorrhapha brachycera.— Larva with parallel jaws directed, 

 or working, upwards and downwards or outwards and downwards, which work in a 

 pricking, chopping, boring, or sucking manner.— (Head not well developed, only a 

 jaw-case without "ganglia being present, which, however, sometimes is similar to a 

 'head because of the outward projecting eyes.) *— Ganglia chain beginning behmd the 

 jaw-apparatus.— Larvge with rudimentary mouth-parts are meta- or amphipneustic 

 and exhibit ten to twelve obvious segments. 



(I.) Tribus Acroptera. 

 Only ten segments after the antenniferous and jaw-case-containing segments, 

 of which the last appears like two grown together. Fam. Lonchoj^eridoi. 



(II.) Tribus Platygenya. 

 Eleven or twelve segments behind the segment that bears the antenna} and 

 mouth-parts, or even apparently more than twelve segments because of sulxlivision 

 of segments. . 



Jaw- or head-capsule either entirely closed at the free parts, strongly chitmous 

 both dorsally and ventrally or membranous ventrally, sometimes very long, some- 

 times short. If only an upper capsule and the chitinous part of the under lip remain 

 free, then it appears flat, formed of straight rods or of a plate running out as a rod, 

 of which the surface-area lies horizontal, or is sometimes absent. 



t Hinder stigmata placed on the last segment dorsally or terminally, as horizontal 

 or vertical fissures, in wliich both the main tracheae open close together, or as 

 separated plates or tubes lying free or in a pit, enclosed l)y lips or processes, or there 

 are tracheal gills on the sides of the body instead of stigmata. _ 



Group Ilomijeodactyla, Cydocera Schin., pp. 



((() Head-capsule permanently exserted, the free part riot retractile into the 



subseciuent segments. («) Notacanfha {Stratiomytdct, Xylophn<jrd(e). 



(6) Head-capsule retractile, the free part capal)le of being deeply withdrawn into 



the following segments : • i i i 



a The upper— to a great extent internal— part of the jaw-capsule, tubular or 



elongate pyriform, simple or formed of long narrow intimately connected 



plates. (b)Tanystoma 



1. Hind stigmata united in a perpendicular fissure. {labanuUe). 



2. Hind stigmata ending separately in two plates or tracheal gills 



Lejnidoe, Acantnomeridai. 



* ThR stwlpjit will do well to tv^at this parPiitliesis as metapliysical. 



