178 NORTH AMERICAN DIPTERA. 



usually most active toward the latter part of the fore- 

 noon, although they are plentiful about cattle and horses 

 during most of the time while the sun is shining. The 

 females only are bloodsucking in habit; the males feed 

 upon the juices of plants, the honey-dew secreted by 

 plant-lice and scale insects, and similar substances. 

 The females also will feed as the males do, when nothing 

 more to their liking is procurable. Their bites are pain- 

 ful, but are not usually attended with that inflammation 

 or swelling characteristic of the mosquitoes and punkies. 



Most species of Tabanidae may be collected in various 

 situations. Sweeping the grasses and weeds of marshy 

 places, collecting from fences and trunks of trees in the 

 early morning, or from plants much infested by plant- 

 lice or certain scale insects throughout the day, netting 

 specimens that fly about stock or the collector's own 

 head, or that may be found upon various flowers, or cap- 

 turing such as may enter the doors and alight upon the 

 windows, all are productive of results. Collections made 

 in these ways are prett}^ sure to represent well the tabanid 

 fauna of any locality. 



The eggs of the Tabanidse are deposited in large masses 

 on the stems and leaves of plants or in similar places 

 over water or in marshy land. They are spindle-shaped, 

 brown or black in color, and, in ordinary summer temp- 

 erature, hatch in from seven to nine days The larvae 

 feed upon various small creatures, and in such cases as 

 have been observed reach maturity and change to pupae 

 the following spring. The pupal stage is completed in 

 three or four weeks, the whole cycle from the deposition 

 of the eggs to imaginal maturity thus requiring about 

 eleven months for its completion. The larvae may be 

 sought for in rotting logs and stumps, in the soil in the 

 vicinity of ponds, under stones about ditches, or swim- 



