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ON THE LIFE HISTORY OF BUCENTES {SIPHONA) 
GENICULATA (DIPTERA: TACHINIDAE), PARASITE OF 
TIPULA PALUDOSA (DIPTERA) AND OTHER SPECIES 1 . 
By JOHN RENNIE, D.Sc. 
AND 
CHRISTINA H. SUTHERLAND, M.A., B.Sc., Carnegie Scholar. 
(From the Laboratory of Parasitology , University of Aberdeen.) 
(With Plate XIV.) 
The Dipterous Family, Tachinidae, comprises a very large number of species 
whose larvae live as parasites within other insects, particularly in their larval 
forms. 
Bucentes (Siphona) geniculata, one of the Tachinidae whose larvae are 
considered in the following paper, is a small ordinary looking fly, blackish in 
colour and showing a somewhat greyish abdomen, with prominent abdominal 
bristles. The labium is long and slender, sharply geniculated about the middle 
of its length, and folded like a clasp knife under the head when not in use 2 . 
In a former paper (1912) one of us has recorded the occurrence of the larva 
of this species as a parasite in the body cavity of Tipula larvae. It is probably 
not confined to one host species. In one collection of Tipula larvae, a pro¬ 
portion of which yielded the parasite, the majority of the survivors, on 
hatching, proved to be Tipula oleracea. In most instances, however, we have 
found the infected insects to be T. paludosa. 
Since the original observation in 1912, we have found this larva regularly 
every year, and consequently regard it as a normal parasite of Tipula. Other 
observers record it from Mamestra brassicae and a related species, Siphona 
cristata, is reported by Roubaud (1906) to occur in Tipula gigantea. 
OCCURRENCE AND DISTRIBUTION OF THE ADULT FLY. 
From an examination of records relating to the adult insect, kindly sub¬ 
mitted to us by the entomologists in charge at the British Museum and the 
Royal Scottish Museum, we find the fly is widely distributed throughout 
This work has been carried out with the aid of Grants from the Board of Agriculture for 
Scotland, to whom we desire to express our thanks. 
A full description of the structure and habits of the adult fly is reserved for a further paper 
