Parasitic disease in batrachia and salmonid^e. 375 
marked with impressions of the smooth-skinned pupae. 
These are distinctly ringed, and when magnified about forty 
diameters show a large number of minute spines. From a 
sketch supplied by Dr. McMunn, the living larvae would 
appear to have been fully a quarter of an inch in length. I 
found that one of the dried, shrivelled, and empty pupae 
skins measured exactly one-fifth of an inch in length. The 
remains of a rather small beetle that had evidently gained 
access to the box were found lodged in the skeleton. This 
had certainly nothing to do with the parasitism, about which 
not a shadow of doubt could exist. 
These facts were recently communicated by me at a private 
meeting of the London Entomological Club held at Dr. E. H. 
Vinen’s house, and I solicited this privilege, as I was unable 
to determine the species of fiy causing the disorders without 
the assistance of entomologists, or, as I might more correctly 
say, dipterologists. The result was most gratifying, as 
in the very lively discussion which then followed, Mr. 
Robert McLachlan, F.R.S., drew attention to recent notices 
in the Zoological Record for 1877-78, and he stated that 
not improbably the larvee in question would be found to 
belong to the genus Batrachomyia of MacLeay. In the 
reports I find that reference is made by Mr. E. C. Rye to 
a note by Herr Boie, on the larvae of a Dipteron attacking 
the soft parts of the mouths of toads in Bohemia. M. Girard 
also gives “ instances of batrachians attacked in a similar 
manner.” Mr. Rye quotes also the opinion of MM. Colin 
de Plancy and E. Taton, that ff the flies ( Batrachomyia) 
attack only sores already existing.” It appears that M. 
Moniez had previously referred some dipterous insects, pos¬ 
sessing these habits, to the genus Lucilia , one species of 
which (L. hominivorax) proves, as everybody knows, so 
terrible to the convicts at Cayenne. The new fly, L. bafoni- 
vora } Mon., lays its eggs “ in the eyes of frogs, and the 
larvee eat into the living batrachian.” Mons. Lelievre refers 
it to L. regalis or L. illustris , Meig., but the opinion is 
disputed by M. Girard. It is also stated that ^larvae of this 
species have been discovered in the head of a toad, near 
Maurenne; and also, in another instance, near Paris. 
From these observations it appears that the instances of 
dipterous parasitism in the nasal chambers of toads, as re¬ 
cently witnessed by Dr. McMunn, and by myself some forty 
years back, are perfectly genuine. 
Every year it becomes more and more apparent how 
largely parasites are concerned in the production of epi¬ 
zootics. 
