NOTES ON METHODS OF REARING AND STUDYING TABANIDS IN 



EARLY STAGES. 



Collecting the Larvce. — The natural habitat of tabanid larvae is the 

 wet mud or sand in the immediate neighborhood of water, hence 

 they are rarely caught by the usual method of collecting aquatic in- 

 sects by means of a net. The lack of a practical collecting method is 

 probably the main reason why these animals while very common 

 have passed almost unnoticed in an epoch of fresh water biological 

 investigations. Neave seems to have employed large nets, as did 

 Hart also, but Neave was able to send out a collecting staff of ne- 

 groes to obtain his material. The use of an ordinary sieve, first ap- 

 plied by Hine to collect the larvae of Tahanns vivax in rapid streams, 

 is more advisable for collecting the larvae from the mud. Patton 

 and Cragg suggest placing lumps of mud and sand with water in a 

 pail; by stirring the mass the large larvae appear floating at the sur- 

 face. The smaller ones are caught when the muddy water is passed 

 through a sieve. 



Rearing Vessels. — The methods of various authors in rearing taba- 

 nid larvae have been treated in connection with the species. Thus in 

 the paragraphs on Tahanus lasiophthaknus and vivax, details of Hine's 

 method in rearing these species are found, and Mitzmain's valuable 

 contributions to breeding technique are found under Tahanus striatus. 



Hine proposes to keep the larvae in jelly glasses the covers of which 

 are perforated by a few holes, and which are half filled with wet 

 sand. Mitzmain uses dishes with some mud and wet filter paper. 



Patton and Cragg have advised the use of very large trays, several 

 feet long and six inches high, in which large numbers of larvae may 

 be reared under almost natural conditions. The bottom of the tray 

 has to have a hole closed by a cork stopper, to make it possible to 

 change the water in the tray from time to time. Pupae should be 

 taken out, as the larvae may injure them, and placed in separate 

 cages, in little vertical holes. Near each pupa a little flag is fastened, 

 bearing the number of the pupa, or other data. 



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