1927] Pilsbry-Bequaert, The Aquatic Mollusks of the Belgian Congo A471 
with the larvee of Driline and Lampyrine, the latter being well known as 
fire-flies and glow-worms. The mouth-parts of the larvx of many Lampy- 
rine exhibit three remarkable features that may be regarded as adapta- 
tions to a snail diet. The mandibles are curved and very sharp and 
provided with an inner channel by means of which the insect injects in 
the snail a fluid that possesses toxic, paralyzing and digestive properties. 
The external mouth-parts are densely hairy and imbibe the partly 
digested tissues of the snail. The pharynx has a bivalve structure acting 
as a suction pump.’ Godard (quoted by Petit de la Saussaye, 1852, p. 
101) describes how the adult Silpha levigata Fabricius and S. atrata Lin- 
neeus, European beetles of the family Silphidx, break the shell of small 
Helices which form a large part of their food. The beetle grasps the 
margin of the aperture between the mandibles and, suddenly jerking back 
the head, pounds the shell against the hard, chitinous plate of the pro- 
thorax. 
In the order Diptera, the larve of certain muscoid flies feed upon 
terrestrial snails. Many valuable observations have been made in recent 
years on these insects, notably by H. Schmitz and D. Keilin? who have — 
published useful accounts of all cases recorded thus far. Some of these 
flies, such as the house-fly (Musca domestica Linnzeus )and many species 
of Sarcophaga, are undoubtedly but accidental parasites of snails, as 
their larve live under a variety of other conditions. Others, however, 
appear to be restricted to snails. The best known of these is Melinda 
cognata (Meigen) in Europe: its larva is a specific internal parasite of 
living Helicide; the eggs are laid in the mantle cavity of the snail; 
upon hatching the young larva bores into the kidney, where it lies with 
1One of the best accounts of the methods used by the larva of the European Lampyris noctiluca to 
attack snails, is that of Newport, G. 1857. ‘On the natural history of the glowworm (Lampyris nocti- 
luca).’ Journ. Proc. Linn. Soc. London, Zool., I, pp. 40-71. The older literature has been brought 
together by Rupertsberger, M. 1880. ‘Biologie der Kafer Europas.’ (Linz a.d.Donau), pp. 165-170. 
See also Bugnion, E. 1922. ‘Etudes relatives 4 l’anatomie et 4 l’embryologie des vers luisants ou 
Lampyrides.’ Bull. Biol. France et Belgique, LVI, pp. 1-53. 
Cros, A. 1924. ‘Pelania mauritanica L. Variations, mcoeurs, évolution.’ Bull. Soc. Hist. Nat. 
Afrique du Nord, XV, pp. 10-52. . 
2Schmitz, H. 1917. ‘Biologische Beziehungen zwischen Dipteren und Schnecken.’ Biol. Zentralbl.; 
XXXVII, pp. 24-43. : ake 
Keilin, D. 1919. ‘On the life-history and larval anatomy of Melinda cognata Meigen parasitic in 
the snail Helicella (Heliomanes)virgata Da Costa, with an account of the other Diptera living upon mol- 
lusks.’ Parasitology, XI, pp. 480-455, Pls. xx1—xxv. ‘ ; 
1921. ‘Supplementary account of the dipterous larve feeding upon mollusks.’ : Parasitology, 
Mokrzecki, S. 1923. ‘Ueber den Parasitismus von Fliegen im K6rper von Land-Schnecken.’ 
Zeitschr. Wiss. Insektenbiol., XVIII, pp. 185-137. ; 
Another interesting record is that of L. Mercier (1921, Ann. Soc. Ent. Belgique, LXI, p. 164) who 
bred the sciomyzid Salticella fasciata (Meigen) from living Helix pisana in France. | 
