D. Keilin 
451 
EPHYDRIDAE. 
Discomyza incurva Fallen. The larvae of this fly were found by von Bergen- 
stamm (1864) in a dead H. pomatia. The pupae are fixed inside the shell in 
the same way as those of Phora bergenstammi Mik. I found near Paris one 
shell of H. pomatia containing a few of these pupae. 
SCIOMYZIDAE. 
Ditaenia cinerella Fallen, obtained by Schmitz (1917) from a shell of a 
Helix collected near Zaragoza, Spain. 
Salticella fasciata Meigen. Perris (1850, pp. 122-123) found the larvae in a 
dead Helix pisana. According to Schmitz (1917, p. 29) it is not yet proved 
whether they are parasites or saprophagous larvae. 
DRYOMYZIDAE. 
Dryomyza sp. Schmitz recorded this fly as a not very common inhabitant 
of dead snails. • 
SEPSIDAE. 
Nemopoda cylindrica Fabricius, bred by me from the larvae found in different 
dead snails. The eggs are of a peculiar shape having a very long filiform pe¬ 
duncle. These larvae occur also in the excrement of different domestic animals. 
BORBORIDAE. 
Borborus, Sphaerocera and Limosina have been recorded by Schmitz (1917, 
p. 30) from dead snails, but they occur also in all kinds of decomposed organic 
substances and especially in manure. 
PSYCHODIDAE. 
Philosepedon phalaenoides L. I have often found the larvae and pupae of 
this species in different species of decomposed snails (see Keilin, 1911, p. 30). 
Philosepedon humeralis Meigen was recorded in dead snails by Westwood, 
Verrall, and recently by Schmitz (1917) who bred this insect from snails 
collected in Lisbon, Zaragoza and Maastricht. 
APPENDIX. 
Observations of M. E. Seguy on Muse a domestica larvae 
DEVOURING LIVING SNAILS. 
On 24. iii. 1919 I received from M. E. Seguy of Rambouillet, France, a 
letter in which he communicated several of his unpublished observations 
bearing upon the relation between the house-fly and snails. The following is 
a summary of his letter: 
He collected several snails, having the shell closed by the epiphragm, and 
examined them, breaking the latter, in the hope of finding the Phorid larvae. 
The snails secreted another epiphragm, but ten days later they were destroyed 
by the larvae of Musca domestica. 
