156 



BRANCH ARTHROPODA 



Horse-flies (Tahan'tilir) are also pests of man and beast. They are 

 most abundant in the hot summer days. The large black-bodied horse- 

 flies, of which there are a hundred species, belong to the genus Tahanus. 



The Bot-flies (CE'siridce). — " The horse bot-fly (Gastroph'ilus e'qui) closely 

 resembles the honey-bee in form, except that the female has an elongated 

 abdomen curved under the body." Horses have an instinctive fear of this 

 fly. It attaches its eggs to the hair of the legs and shoulders of the horse, 

 and they are taken into the mouth by biting the irritated place. The 

 larvse fasten themselves to the lining of the stomach. A\ hen gro\\ n, during 

 the fall and winter, they pass out and develop within a puparium. 



The oxwarble larvae {Hypoder'ina linen' la) live just beneath the skin on the 

 backs of cattle, which are made frantic by their burrowing. 



The sheep bot-fly deposits its larvae in the nostrils of sheep, antelope, etc. 

 They work up into the frontal sinuses and horns and cause the " staggers."' 



Reindeer, deer, rabbits, and squirrels are infested by lur\U' of speeies of 

 bot-flies, and one or two species infest man. 



Fig. 126. — 1, Egg-mass of the common mosquito; 

 at the surface of the water; 'A, a pupal mosquito. 

 Leaflet.) 



arva breathing 

 (From Hampton 



Mosquitoes {Culic'idat) (Fig. 12.5) seem too well known to need descrip- 

 tion, but there are other insects so similar that they are often mistaken for 

 them. Comstock says " the most distinctive feature of mosquitoes is the 

 fringe of scale-like h;iir on the margin of the wing and also on all known 

 American forms on each of the wing veins . ' ' The males differ from the females 

 in having feathery antennae and in the absence of the piercing stylets. As 

 a rule they do not sing or bite, and probably feed upon the juices of plants, 

 as do the females if they cannot "get blood." The larva^ (Fig. 12ti), called 

 " wrigglers " or " wiggle-tails," are too often found near our dwellings in 

 rain-barrels, slop-pails, open cisterns, open sewers, water troughs, lily-tubs, 

 ponds, anywhere where the water is allowed to rcMuain long enough for their 

 development, which requires from eight to eighteen days. Of the three 

 principal genera, Cfilex contains most of our mosquitoes wlmse bite and song 

 are well known. Aiinph'rUs is the genus which is the intermediate host 

 and the transmitter of the malaria germ. Of course it cannot transmit 



• Comstock, p. 47S; Hertwig, p. 493. 



