FLIES. 



417 



523. Mouth-parts 

 of horse fly. 



FIG. 524. Tabanus bovinus. 



as they are called, are wholly adapted in the female for piercing. The male, as in the 

 other blood-sucking flies, is a harmless fellow, and spends his time in meadows, on the 

 barks of trees sucking up the sweetened sap, or on flowers seeking 

 honey. The female every one has noticed flying about with a dis- 

 tinct humming tone ; the larger species will be observed to follow 

 cattle or horses, repeatedly seeking to find a place upon the animal's 

 back where she will not be molested. Their power of flight is 

 great ; often they will be seen to poise in the air perfectly motion- 

 less, then in a flash darting away ; the fastest speed of a horse will 

 not elude them. Their bites, though painful enough, do not appear 

 so irritating as those of the mosquitoes and Simulidae. The large 

 puncture they make will often allow the blood to flow after they 

 have withdrawn the proboscis, but apparently they do not leave any saliva in the 

 wound. Blood, however, is not their only food ; when nothing better offers, they 



will, like their males, seek the juices of plants and trees. 



The male's eyes are contiguous on the top of the head, 

 indeed the large head in both sexes is chiefly composed of 

 the eyes, which often have most brilliant iridescent markings 

 upon them. That they can see for a long distance seems 

 certain. On the uninhabited plains east of the Rocky Moun- 

 tains, the writer has frequently seen them coming from a 

 long distance, attracted by the sight of the horse upon which 

 he rode. 



Over thirteen hundred species are known throughout the 

 world, and nearly one hundred and fifty in North America. Many are among the 

 largest and most powerful of Diptera, but the largest number are of moderate size, 

 though none are small. Most of them love the bright sunshine, though many seek 

 shady places near the borders of woods, appearing during bright, sunshiny days. 



The spindle-shaped brown or black eggs are found in spherical or flat groups, stuck 

 together, and attached to the leaves or stems of grass and other plants ; those of the 

 aquatic larvae are fastened to rushes. The larvae are carnivorous ; many live in the 

 earth, others in water. They are predaceous, often upon snails and injurious insects, 

 thus in a measure repaying the agriculturist for the molestation they cause him. The 

 young larvae are known to penetrate beetle or other larvae and remain within them 

 till they have completely consumed them, and their enlarged bodies have filled out the 

 skins. Thus the larvae of Ifcematopota have been observed feeding upon Helops, 

 and those of Tabanus upon Noctuoe. 



Therioplectes cinctus is a large species that may often be seen in New England ; it 

 is black in color, with a broad, orange-colored band at the base of the abdomen. A 

 more common species occurring throughout all the Eastern states is Tabanus atratus ; 

 it is deep black throughout, but with a whitish pruinose dust, especially on the abdo- 

 men. Tabanus llneola is also very common, but smaller ; it is so called from the 

 presence of a whitish line on the abdomen. 



The family LEPTIDJE will be readily distinguished from the Tabanidae by the 

 simple, not annulate, third joint of the antennae, which is provided with a simple 

 or thickened styliform bristle. Very differently, however, from that family, the 

 species in this, except in the single genus Symphoromyia, are wholly unable to bite 

 or draw blood. The family comprises two hundred known species throughout 

 VOL. ii. 27 



