October, '17] MARCHAND: REARING TABANIDS 471 



of single larvae, although it would be cumbersome for rearing large 

 numbers. Several dozen, however, can be taken care of easily by one 

 worker with daily inspection of all the tubes. 



The damp filter paper gives to the larvae a perfect substitute for the 

 damp mud in which they usually live and is also similar in contact, 

 facilitating their natural movements upwards and downwards in the 

 tube. They pupate without difficulty in the test tubes and usually in 

 the upper portion of the roll of paper. Pupae were obtained in this 

 way from four species of Tabanus.^ The pupae are easily taken out of 

 the test tubes and placed in other dishes or jars, but two males of 

 Tabanus lineola were allowed to hatch in the test tube; of these one 

 had the wings fully developed, and the other one had one wing slightly 

 distorted, having been hindered in its development by the filter paper 

 which had become dry and somewhat hardened. Larvae of 4 to 5 mm. 

 in length did just as well as those of 40 mm. and more in length. The 

 filter paper is taken out from time to time with a forceps and renewed, 

 but if one wishes merely to keep the larvae alive and to rear the adults, 

 this may be omitted and all that is necessary is to keep the filter paper 

 moist and to give new food from time to time. When the paper be- 

 comes dry or the larvae are very hungry, they will sometimes succeed 

 in escaping by creeping underneath the cheesecloth in spite of the 

 rubber band holding it, but this happens only occasionally. In fact, 

 the larvae need very little care and with this rather simple breeding 

 apparatus, it should be a comparatively easy task to obtain detailed 

 data on the life-history of any Tabanid species. 



Test tubes have already been used for the rearing of Dipterous 

 larvae, notably by J. P. Baumberger, for rearing Drosophila aynpelophila 

 on agar, but for earth- and mud-inhabiting larvae a convenient method 

 was lacking. The test-tube-and-filter-paper method may prove useful 

 for the rearing of many such larvae, as those of Tipulidae, Stratiomyiidae, 

 possibly of Lampyridae, etc. 



A few words may be added here about collecting the larvae. I have 

 first followed the method employed by Patton and Cragg, who recom- 

 mend using a pail in which mud and sand from the edges of rivers and 

 ponds is mixed with water and thoroughly stirred and the muddy 

 water then sifted. Those larvae which are able to float appear very 

 soon at the surface; the others have to be obtained by sifting. Finding 

 it inconvenient to wander about with a spade and pail, taking samples 

 from different localities, I soon contented myself with an ordinary 

 kitchen sieve by means of which excellent results may be obtained 

 with very little trouble. Moderate-sized lumps of mud and sand, 



^ Since this paper was written, pupae were obtained of fourteen species of various 

 Tabanidse: Tabanus, Chrysops, and Haematopota (?). 



