92 Larval and Pupal Stages of Bibio Johaniiis L. 



Hitherto there has been no complete account of any Bibionid larva, 

 but only partial descriptions and fragmentary accounts of the life- 

 history. 



On account of the frequent occurrence of larvae of this family, and 

 their possible economic importance in certain cases, I have been led to 

 investigate the present species as fully as possible. 



The earliest description of the larva and pupa of any species of Bihio 

 met with, is that given by Reaumur (1741). Reaumur describes and 

 gives figures of the larva and pupa of the " St. Mark's Fly "' {Bihio Marci), 

 but, as with all other figures of larvae and pupae of this genus seen, the 

 figures are not sufficiently clear for purposes of identification of species. 

 De Geer (1776) gave the first account and figures of Bibio Johannis 

 and in 1832 Lyonet gave a description of Bibio Marci. Bouche in 1834 

 described and figured the larva and pupa of Bibio hortulanus, and also 

 figured the mouth parts of the larva, but these figures again are very 

 indefinite. Westwood in 1840 referred briefly to the larva of this genus 

 and gave a small figure. In 1872 Beling described the larvae and pupae 

 of a number of species of Bibio and Dilophus, amongst others those of 

 Bibio Johannis. Needham in 1902 gave an account of the occurrence 

 of swarms of the larvae of Bibio fraternus, with descriptions and figures 

 of the larva and pupa, while Sharp (23) has figured a larva of an un- 

 named species of Bibio, and has also given a figure of a portion of the 

 integument of the larva. 



In addition to these accounts there are several records of the finding 

 of larvae of different species of Bibio in great numbers in a small area (13) 

 and references to damage done by them to cultivated plants. The larvae 

 of the different, species of Bibio appear to be very similar, which makes 

 identification of the larvae difficult. 



2. THE EGG. 



The egg (Text-fig. 8, p. 1 12) is -63 to -66 mm. long and -13 to -15 mm. 

 broad. It is cylindrical with rounded extremities, and is approximately 

 straight. The eggs are not shiny but have rather an opalescent appear- 

 ance owing to their being covered with small pointed projections. They 

 are at first of a uniform light straw colour but after a few days a darker 

 patch appears at each end. 



