94 AN ACCOUNT OF BRITISH FLIES. 
method of leaping, resembling the “hop” of a flea, the hind legs 
being adapted to this use. When found out of doors, many 
(Mycetophila) may be taken in damp ground, and others in plenty 
near and around fungi, especially when they are somewhat decayed. 
Many are (Sciophi/a) short lived; others (J/ycetophila) hibernate, 
and appear in the early spring, and according to Heeger, “ copulate 
after a few days, generally in the evening. After six or ten days the 
female, if the weather is moist and rainy, lays its eggs on the fungi 
growing on old horse-chestnuts, singly, twenty or thirty on the same 
fungus. The larve hatch after eight or ten days.” 
The “ fungus gnats” have not been studied in the same way the 
Cecids have, and our knowledge of them is not very satisfactory. 
Recently some good work has been done on the Continent, especially 
in Russia, by Dziedzicki, whose “ Monograph of European Phronie”* 
is of great value. The small size and the absence of damage done 
by the larvee has hindered their study in such detail as has been done 
in the Cecidomyidze. Some few are certainly injurious, as the 
species that live upon the “‘ Mushroom,” whole frames of this edible 
fungus being destroyed by these larvae; but the amount of damage 
done is small compared to the amount of good which these maggots 
do in destroying fungi. 
The ? lays her eggs generally on the under surface of the pileus 
(Mycetophila), walking about ovet the surface first to find a suitable 
place, then depositing the ova singly. Others (.Scéara) lay their eggs 
in decaying vegetable matter; they may, as in somé of this genus 
(Sctara) be laid in long strings. The eggs are white and cylindrical, 
and vary from 4 to 4 of a line in length. 
The larve hatch after eight or ten days. The account of the | 
larvee is mainly taken from a paper kindly sent me by C. R. Osten_ 
Sacken,t which gives a concise and full description of the structure 
and habits of JZycefophi/a larvee. In this paper he gives the follow- 
ing characters of the larvee : 
“A distinct horny head; a fleshy labrum, encased in a horny 
frame ; horny flat lamelliform mandibles, indented on the inside ; 
maxillze with a large coriaceous inner lobe, and a horny outside 
piece, with a circular excision at the tip; labrum horny, small and 
almost rudimentary ; body fleshy, with eight pairs of stigmata.” 
The antenne are mostly rudimentary (AZycetophila, Sciara) and 
spring from a pit on each side of the mouth; they are often only 
“fleshy swellings,” but in some (Soditophila) they are distinctly 
* Flor. Ent. Rossland, xxiii. 
y Characters of the larvae of AZycetophilid. 
