PAEASITES OP ANIMALS. 45 



D. Gfallopavonis infests the turkey. The body is marked 

 by peculiar, delicate, transverse strias, and with numerous 

 small circular impressions on the back. 



D. avium torments small cage birds, like the canary. It 

 often takes refuge in cracks about the perches, wliich should 

 therefore be kept clean. 



AEG AS Latreille. 



This genus includes the famous Ar^as Persicus, which 

 infests old dwellings in Persia, especially at Miana, and is 

 said to be so poisonous that its bite produces convulsions and 

 speedy death ; or even its juices, if crushed upon the skin, 

 may produce the same results. 



These are larger than most of the mites, and somewhat 

 resemble the ticks. The body is broad-oval or roundish. 

 The upper side of the head so projects as to conceal the mouth 

 parts. The jaws are suctorial. The lower side of the body 

 is granulous, not scaly, and covered by a single piece. 



Arg-as reflexus Latreille lives upon pigeons and sucks their 

 blood. It especially infests the young, upon which there are 

 sometimes great numbers. The body is marked with curious 

 tortuous grooves and .pits. The color is yellowish, but when 

 filled with blood violaceous. 



IXODES Latreille. (Ticks). 

 These are the largest of the Acarians, and all are parasitic, 

 chiefly upon quadrupeds and reptiles, but sometimes on birds. 

 The body is broad-oval or round, and when not swollen with 

 blood is flatish, and the integument is firm and tough. Their 

 mandibles (Figure 43, b,) are covered with teeth and have ter- 

 minal hooks ; their maxillas are small, not reaching beyond the 

 beak, but bear a peculiar organ called the glossoid (Figure 

 43, a,) also covered with hook-hke teeth. The legs are slender 

 and have two claws, and in the young have pads or suckers 

 (d). The young are six-legged (Figure 42). The ovarial 

 opening is near the mouth, between the first pair of legs. 

 These parasites, when young, cling in large clusters to the 

 tips of leaves and twigs of herbs and shrubs, with part of 

 their six slender legs extended. When brushed by a passing 



