152 [March 



Leon Dufour,* in his paper on the metamorphoses of fungivorous larvae, 

 made the first and only attempt at a generalization of the characters belong- 

 ing to the different genera of the family. He divides these larvae in onten- 

 natse (Bolitophila) and non-antennatx ; the latter are subdivided in oculatse 

 (Mycetophila, Cordyla) and non-oculatse (Sciara). But it will be shown 

 below that the antennge may be considered as always extant, although fre- 

 quently in a rudimentary state. It is difiicult to say what Dufour took for 

 the ocelli; if it was the pair of small, pellucid, convex spots, which may be 

 perceived below the antennae, he was correct in stating that they are absent 

 in Sciara ; but how did he not perceive them in Bolitophila ? (" Mes in- 

 vestigations les plus repetees, says he, ne m'ont fait reconnoitre ilans les 

 anfennees, ancune trace d'yeux.") As to the trophi, their description is 

 very imperfect; the author indistinctly perceived a pair of serrated man- 

 dibles, but did not discover any maxillge nor palpi. He gives, however, 

 very valuable observations on the internal anatomy of these larvae. 



Bouche has described several larvse of Mijcetophila and Sciara, but, 

 besides giving an idea of their general appearance, these descriptions have 

 little value. The statements about the trophi are very imperfect ; the 

 figures appended to them are incorrect. (Thus the mandible of M//c. 

 signata, Tab. III., f. 7, or the head and mandibles of Sciara, Tab. III., 

 f. 11, are altogether imaginary.) 



Heeger, likewise, has published observations on a Sciara and a Myceto- 

 phila. The paper on Sciara contains the only correct description and 

 figures of the trophi of any larva of this family hitherto given. In the 

 article on Mycetophila, on the contrary, Heeger has committed a most sin- 

 gular error, in taking the back of the larva fur its venter, and vice-versa. 

 The trophi are not mentioned at all. 



In the sequel I have attempted to establish the general characters of 

 the lar\(t! of this family, and to show at the same time the modifications 

 which these characters incur in the principal genera. My statements are 

 principally based upon my own observations on the larvse of Mycetophila 

 aignata. (or a closely allied species), of Bolitophila cinerea, M., Sciophila 

 linhatella Zett, and several species of Sciara, all of which I have reared. 

 I had, moreover, a larva found under the bark of a tree in Virginia, and 

 which I have some reason to suppose to be that of Lfy'a. 



It is on the examination of these larvae, supported by scattered state- 



'ments found in previous authors, that I have tried to define the characters 



of this family and of the genera. These characters may, and probably 



■■■ All the quotations lui ve to be looked for in the Beferences, at the end of this ])aper. 



