210 
Bucentes (Siphona) geniculata 
hooks, one series pointing backward, the other forward. The rounded contour 
of the first segment is broken by the slightly projecting anterior spiracles, 
which are directed laterally outward. Posteriorly the puparium narrows 
distinctly into a short tubular portion which terminates in two bifurcated 
lobes, the post-abdominal spiracles. In the intersegmental space which 
separates the first and second abdominal segments are a pair of holes situated 
on the latero-dorsal side. 
In a future paper we hope to deal with certain gaps in the foregoing 
account of the life history and to give a description of the structure and habits 
of the adult fly. 
«/ 
ACKNOWLEDGMENT. 
We desire specially to express our thanks to Dr D. Keilin, of the Quick 
Laboratory, who has generously placed his extensive knowledge of the litera¬ 
ture at our disposal, and also been most helpful with friendly criticism and 
suggestions. We have further found his recent work on the life-history and 
larval anatomy of Melinda cognata Meigen, parasitic in the snail Helicella 
(1919), of much assistance in determining the morphological details of the 
various larval stages. 
REFERENCES. 
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x. 248. 
Keilin, D. (1919). Life history and larval Anatomy of Melinda cognata Meig. parasitic in 
Helicella virgata, Da Costa, etc. Parasitology, xi. 430. 
Knuth, P. Handbook of Flower Pollination. English Translation, Oxford. Vol. m. 1909. 
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Entomol. Meddelelser, 2 R. iv. pp. 28-42. 
— (1918). Tachin-Studier. Vidensk. Medd. fra Dansk naturhist. Foren. lxix. 247-262. 
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exterieurs, la biologie et l’anatomie d’une larve parasite du groupe de Tachinaires. 
La Cellule, xv. 290. 
— (1909). Recherches sur les Dipteres a larves entomobies. La Cellule, xxvi. 173. 
Rennie, J. (1912). Note upon a Tachinid Parasite ( Bucentes geniculata de Geer) of Tipula 
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