40 Dr. D. Keiliti o?i the Larvce d:c. of 



The study of the larvre and pupfe of Ditomyia and Sipn- 

 merus shows clearly the great similarity in structure of nearly 

 all their organs. It also shows, on the other liand, tlmt the 

 larval and pnpal structure of these two genera is totally 

 difierent from that of all the Mycetophilidae. 



The difference is especiall}' striking in the strncture of 

 the antennae, mandibles, maxi!l?e, and labium, with their 

 palps, the sensory organs, respiratory system, structure of 

 the spiracles, the salivary glands, and, finally, the form of the 

 puppe. 



These two genera must therefore be re-united in a special 

 family, the Ditomyidte, which itself must be completely 

 separated from the family of the Mycetophilidte. 



From tlie study of the larval and pupal characters it 

 follows that the family Ditomyidae must occupy among the 

 Diptera Orthorrliapha Eucephala, of Braner, a position 

 equally important with that of the Mycetophilidre, Bibioni- 

 nidae, Rhyphidse, &c. 



As to the relations of this new family to the others we 

 can state only that tlie larvae of Ditomyidae bear a closer 

 resemblance to the larvae of Bibionidae than to those of any 

 other Diptera, and more especially when we compare their 

 labra, mandibles, maxillae, and the structure of the spiracles. 



The subfamily JNIycetobiinae of Winnertz (1861), composed 

 of the genera Mycetobia, Mesochria, Ditomyia^ and Synimerus, 

 must therefore completely disappear, as il/yce/oiia (and witli 

 it, accoiding to Edwards, Mesochria) must be transferred to 

 tlie Rhyphidae ; while the two others go to form a separate 

 fan:ily, Ditomyidae, completely separated from Myceto- 

 philidae. 



I must express here my best thanks to Mr. F. W. Edwards 

 for sending me the specimens of Ditomyia and Symmerus 

 larv!«. I may say that it is his re-discovery of these larvte 

 which has enabled me to accomplish this study. 



References. 



DuFOUR L. (1849.) " Histoiie des Metamorphoses du Rhyphus fenex- 



tralis et du Mycetobia •patlipes." Ann. de la Soc. Eutoiii. de 



France, '1* serie, t. viii. pp. 195-210, pi. 7. 

 EiiWAEDS, F. W. (1916.) " On the Systematic Position of the Genus 



Mycetobia^ Mg. (Diptera Nematocera)." Ann. & Mag. Nat. liist, 



ser. 8, vol. xvii. pp. 109-110. 

 . MS. Notes on Ditomyia and Synnnerus, see pp. 36 & 39 of this 



paper. 



