6 OHIO STATE ACADKMY OF SCIENCE. 



The pupae studied are dull yellowish in color, with an en- 

 circling row of spines or stiff hairs at the apical third of each 

 abdominal segment. Characters for grouping the various species 

 are located'in the spiracles, and also in the denticles at the apex 

 of the abdomen. 



When the larva is first hatched a certain amount of yolk 

 is present in connection with the alimentary canal, and this furn- 

 ishes it food for a time. The young larvse of all the species 

 studied in this stage possess the burrowing habit, and whatever 

 soft material, plant or animal, they can reach they at once bur-, 

 row into. Consequently little opportunity is offered under nat- 

 ural conditions for studying their habits and growth. The larvae 

 of many of the specimens probably remain in the water or in 

 the mud very near the edge of the water throughout the existence 

 of this stage for their pupse come to the surface of the ground a 

 few inches from the edge of the water just before the adults 

 issue ; and around fresh water ponds I have observed myriads 

 of pupa skins of Chrysops with just the anterior ends projecting 

 above the surface of the ground. There is a wide range of vari- 

 ation in the habits of larvse of various species of Tabanus. Some 

 are hatched in stagnant pools, some in ripples of streams and somr 

 in marshy ground. Some species live in water for a time and 

 crawl out into dry ground ; consequently one often finds Tabanid 

 larvae by digging in dry ground along the borders of ponds. 

 Larvae are easily reared if taken when nearly full grown, and 

 appear to be as much at home in moist ground as in water. They 

 eat small, soft-bodied invertebrates of many kinds, even their 

 own species. We have kept them from fall until the following 

 spring in small covered dishes filled with wet earth. Plenty of 

 moisture was applied and earthworms from a greenhouse near 

 by were given for food. In order to prevent one larva from 

 eating another of its species, only one was kept in each dish. In 

 a large number of trials only a few have died before reaching 

 maturity. 



Not much can be said regarding the length of time oiir 

 species remain in the larval stage, but from circumstances one 

 is led to believe that, in some cases at least, more than one yea;: 

 is consumed by this stage. At Sandusky, Ohio, in July, 1901, 

 Tabanus stygius was very common, but in 1902, at the same 

 place, only one or two specimens were seen. It may be that one 

 can account for this difference on the ground of more than one 

 year being required for the completion of the larval stage. 



FIELD HABITS OF THE ADULTS. 



The adults have many peculiar habits which the collector, 

 should know in order to become proficient in procuring speci- 

 mens ; and besides, some of these habits have an economic bear- 

 ing also. The larval stage is passed in the water or at least in 



