HABITS AND LIFE HISTORIES OF TABANID^. 25 



where they were so abundant earlier in the day. Either they had 

 gone in search of food — the females to different animals for the pur- 

 pose of sucking blood and the males to various places where they could 

 find nectar and other liquid substances to their liking — or else they 

 had gone to the water, over which could be seen both sexes flying in 

 abundance, now and then striking the surface with their abdomens, but 

 flying so rapidly that the observer had difficulty in determining the 

 nature of their actions or what v/as accomplished by them. However, 

 if the day was dark and cloudy there was not much activity among 

 them, and on some of the cooler days or when it was raining they 

 were hardly ever seen at all. An acquaintance with their habits at 

 such times revealed the fact that they were passing the time among 

 the foliage, usually on the underside of a leaf, where they remained 

 quiet until pleasant weather appeared again. 



The habits of the sexes while flying over water have been investi- 

 gated a great deal, but after all there are some points not fully under- 

 stood. There appears to be no choice as to the kind of water, for 

 running brooks are chosen as well as stagnant ponds. At first there 

 was some question in my mind as to whether both sexes have the habit 

 of striking the surface in their gyrations over water, but observation 

 soon proved that one sex as well as the other visits ponds and streams 

 regularly, and so far as I could see there is no difference in their 

 habits so far as the dipping is concerned, and specimens taken in the 

 act bear out this statement. Over a small pond in which there was 

 an abundance of aquatic vegetation in parts and open water in other 

 parts, 1 observed many of the insects flying. Specimens, after flying 

 about for a time, often came to rest on the foliage and sometimes on 

 the surface of the open water. Under such circumstances the sex 

 could be determined readily. Along swiftly flowing streams speci- 

 mens found favorite resting places on the stones that protruded above 

 the water, or else on the bank near the water's edge. 



The food habits of the adults are of especial interest, and every 

 opportunity for studying these was utilized. I am thoroughly con- 

 vinced that the females take much other food than blood and do not 

 believe it would be overstating the facts to say that specimens of this 

 sex may pass the period of adult life without taking blood at all. Both 

 sexes of sulcifroiis run over foliage a great deal and often have been 

 observed sipping up water that forms on the leaves as dew. This 

 dew in man}" cases carries nourishment in solution, and on trees 

 infested by aphides, scale insects, and various other species, espe- 

 cially of the order Hemiptera, much food material is included. Many 

 leaves become coated with honeydew dried to a semisolid state. The 

 water that collects on these leaves during clear nights dissolves some 

 of this material and makes it available as food for horseflies. I have 

 watched many specimens on wet stones and damp sand along brooks. 



