38 



HA RD WICKE'S SCIENCE- G OSS IF. 



following: — Mergen's " Systematische Beschrei- 

 ^""g»" 5 vols. 1818-1838, Germany. Macquart, 

 "Diptcres," 2 vols. 1S34-1835, France. Zetterstedt, 

 "Diptera Scandinavia," 14 vols. 1842-1860, Scan- 

 dinavia. Rondani, " Diptera Italicce," 7 vols. 1856- 

 1871, Italy. Schiner, "Fauna Austriaca," 2 vols. 

 1862-1864, Austria. Desvoidy, "Dipteres des 

 Environs de Paris," 2 vols. 1863, France. 



The only catalogue of European Diptera is that by 

 Schiner, published in 1864, giving about 670 genera, 

 and 8600 species as European. 



Schiner and Loew are, perhaps, the best recent 

 Continental writers, and as no linear arrangement of 

 families (entirely consistent with the structural 

 characteristics of the various families) is possible, I 

 shall adopt the sequence of Mr. Verrall in his lately 

 published list as being the best and most recent 

 authority on British Diptera. 



Schiner (1862) gave a large quantity of introductory 

 matter relating to the structure of the Diptera, but 

 in his table of Brachycera families he, as Walker did, 

 makes some families {Etnpidcc, Dolichopida:^ and 

 Conopida:) fall in both his primary divisions — which 

 appears to me very undesirable ; though I must add 

 that I cannot myself suggest any table of families 

 which shall be flawless in this respect. 



In 1864 Schiner proposed dividing the Diptera 

 into two great divisions — OrtJiorkap/ia, in which the 

 pupa is sometimes coarctate, but in all cases the 

 larva skin is slit longitudinally in the dorsal portion 

 to give exit to the pupa or perfect insect ; and 

 Cyclorhapha, in which the pupa is always coarctate, 

 the perfect insect escaping by throwing off a sort of 

 lid at one end of the dried larva skin which forms the 

 cocoon. 



In the same year Lioy submitted another classifi- 

 cation. 



Schiner, in 1864, estimated the described species 

 of Diptera at about 19,449, distributed as follows : — 

 Europe, 8670 ; Asia, 2046 ; Africa, 1644 ; 

 America, 5517; Australia, 1056; of unknown 

 locality, 516. 



In 1868, the " Zoological Record" considered over 

 20,800 species had been described. 



Brauer's classification, in 1869, was on larval cha- 

 racters : — 



Orlhorhapha:— 



Nematocera, three groups (twelve families). 

 Brachycera, three groups (fourteen families). 



Cyclorhapha: — 

 T Proboscidea : 



Group I, SyrphidcE. 



Group 2, MiiscidtE (including ConopiiUc, Plp7inciiUdce, 

 and Platypezidce as divisions of Miiscida). 



Eproboscidea : 



Hippoboscidce and Nycteribiidw. 



In 1878, Osten Sacken produced another new 

 arrangement of groups and families : — 



I. Oithorhapha. — He does not subdivide these 

 further than into families (most of these are the 



families of Brachycera and Nematocera, given in this 

 paper). 



2. Cyclorhapha. — Syrphidcc, Conopida:, PlatypczidtVy 

 Piptmcidida:, Oestridic, JlliiscidiC (he raises all mj' six 

 sub-families of Miiscida:, and all the groups of 

 Acalypterata, to the rank of families), Phoridcc. 



3. Pupipara. — ITippoboscidic, Aycterilnidic. 



I have not adopted either Schiner's or Brauer's 

 latest systems ; as, in a paper intended specially for 

 beginners (as this is), it appears to me the tables 

 should be based on characters of the perfect insect, 

 not on those of the larva or pupa, with which the 

 student probably would not be familiar. At the 

 same time, I fully recognise that the structure of the 

 pupa case is of the highest importance in classifying 

 the Diptera. 



5. DESCRIPTIONS AND TABLES. 



In the Diptera the mouth is suctorial, the proboscis 

 usually being rather long ; there are two maxillary 

 palpi ; the thorax is compact, the pro-thorax and 

 meta-thorax being very short, and the meso-thorax 



Fig. 27. — AA, costal vein, i, first longitudinal vein (often 

 double) ; 2, second ditto ; 3, third ditto ; 4, fourth ditto ; 

 5, fifth ditto ; 6, sixth ditto, or anal vein ; 7, axillary vein ; 

 w, internal transverse vein ; I,, external ditto ; aa, costal 

 cells ; b, marginal cell ; c, submarginal cell : d, first posterior 

 cell ; (', second ditto ; /, third ditto ; g, discoidal cell ; 

 hhh, basal cells ; x, costal spine (often absent). 



much enlarged ; forming the greater part of the 

 thorax ; the scutellum is rather large ; the abdomen 

 is usually formed of from five to seven segments ; the 

 wings are two in number, the posterior pair being 

 replaced by alulje, and a pair of filimentary appen- 

 dages, clubbed at the tip, known as halteres ; the 

 legs vary greatly in size and length, the tarsi being 

 pentamerous. 



The Pidicidit: (fleas) do not appear to me to be true 

 Diptera ; so, although Mr. Verrall includes them in 

 his list, I have eUminated them, as does Schiner irv 

 his "Fauna Austriaca." I may observe, however, 

 that three genera and thirteen species are British. 



The wing of one of the Anthomyidcc is given, with 

 the terminology adopted by Dr. Meade and other 

 British authorities (after Loew). It is exceedingly 

 unfortunate that there exists such a diversity of 

 opinion in the matter of terminology. 



It is manifestly quite impossible, in the limited 

 space at my disposal, to give more than a bare outline 

 of the characteristics of each family, and a brief de- 



