330 C. R. Osten Sacken: 



and A calypterces. Tlie Calypterees (Calypteratae), althoiigli 

 bcarinj,' thc sanie name as R.-D.'s first family, reprcsent a ditfercnt 

 systematic concept: tliey are Ü\c CalypterataeV\..-D plus \\\?> Äleso- 

 tnydae. Tliis adoption of the sanie name for a different systematic 

 concept was, on the part of Macquart, a great mistake, unless it 

 was done in malice, to spite R.-D., and, in that casc, it would de- 

 serve a severer designation. It became a source of confusion for 

 more than one author, and. among others, as I have sliown, for the 

 Editor of R.-D.'s posthumous work. 



Macquart's publication of 1843 became the starting point of 

 the division of the Mnsculae into Calypteratae and Acalypterafae, 

 adopted by later authors. It owed its success to its fallacious sim- 

 plicity, rather than to any intrinsic merit. And if the name Calypte- 

 rata was ill chosen by R.-D. because the covering function of the 

 squama is not proved, and, at any rate, of but secondary impor- 

 tance, Macquart's name Acalypterata was still more unfortunate 

 and misleading, because it means without sqnamae, although the 

 anterior squama is in most cases present. Macquart's division 

 became, neverthelcss, populär through Walker's Insecta Britan- 

 nica, Diptera, Vol. II, p. 2 (1853) and through Schiner's Fauna, 

 Vol. I, p. LXX (the volume is dated 1863, but the first instalments 

 of it appeared in 1860; conipare Gerstaecker's Bericht etc. 1860, 

 p. 276). The division was not adopted by Loew in his sketch of 

 the Classification of Diptera in the Monogr. N.-Am. Dipt. I (1862), 

 nor do I find any trace of its adoption in Rondani's writings (com- 

 pare, for instance, his survey of the families of Diptera in the Pro- 

 drome I, p. 12, 1856). But Rondan i made use of the terms ca- 

 lyptra and squatna calyptrorurn^ as I shall explain below. 



It seems to me that R.-D. treatment of this question was a 

 rational one, and recent authors have come to the same conclusion 

 that „a distinct limit between Calypterata and Acalypterata caunot 

 be traced" (Girschner, Entom. Nachr. 1895, p. 84). 



II. Robineau-Desvüidy adopted the terms cidllerons and 

 calypta at the same time, at the very beginning of his work of 

 1830. Cidllerons had been previously used by Geoffroy and La- 

 treille (Comp, my paper, p. 286). Hence R.-D. had the right to 

 say (1. c. p. 16): „Je conserve ä ce double appareil le nom fran- 

 yais de cidllerons, mais je le traduis en latin par le mot calypta, 

 de calypto, je couvre." R.-D. always used the word calypta in the 

 plural (in the Myodaires, 1830, p. 153: calyptis limpidis and 

 passirn; in the Hist. Nat. des Dipt. des Env. de Paris, I, p. 55, at 

 top: calypta mediocria). Calyptum, in the singular I have not 



I 



