386 



BUREAU OF ANIMAL INDUSTRY. 



Ixodes ricimis, the castor-bean tick, is common in many States of 

 the Union. (See p. 462.) 



Ixodes hexagonus^ a European dog tick, is found particularly east of 

 the Rocky Mountains. (See p. 467.) 



Aynblyomma americanum, the Lone Star tick, has a very wide dis- 

 tribution on the American continent, and is one of the most easily 

 recognized species found on cattle. (See p. 474.) 



Several other supposed distinct species have been mentioned by 

 various American authors as infesting cattle in the United States, but 

 it is probable that all of them are identical with one or another of the 

 above-named forms. Thus, Amhlyomma unijmnctatufn is identical 

 with A. americanum; Boojpliilus hovis is identical with B. annulai/iis; 

 Dermacentor occidentalis is identical with D. reticulatusj and Ixodes 

 scaptdaris = (?). (We have not yet been able to recognize this last 

 species.) 



In the keys to the various ticks which are published in this paper, 

 the cattle ticks of the United States have been compared with Ixo- 

 doidea found on other animals and also in other countries. The follow- 

 ing artificial key to the above-mentioned eight species will be found 

 somewhat easier to follow until the inspector becomes acquainted with 

 the most common forms: 



Artificial Key to Eight Ticks reported from Cattle in the 



United States. 



[For the Texas fever tick, follow Roman type.] 



1. Scutum present 2. 



Scutum absent 5. 



2. Scutum uniformly dark, or nearly so 3. 



Scutum partially white or yellow 4. 



3. Palpi less than half as long as the capitulum is broad 



Boophilus annulatus, p. 420. 



Palpi as long as the capitulum is hroad^ or even longer 



Ixodes ricinus^ p. 462, and I hexagonus^ p. 467. 



4. A single hright sjjot at posterior angle of female scutum 



Amhlyomma americanum^ p. 474. 



WJiite extends to anterior portion of female scutum 



Dermacentor electus^ p. 455, and D. reticidatus, p. 448. 



5. Found in the ear,' body violin-shaped 



Ornithodoros Megnini^ p. 408. 



Body oval; tegument with radiate lines of dots 



Argas miniatus^ p. 402. 



It is needless to state fhat this key is given only as an additional aid, 

 in the way of a "ready reference," to help inspectors to become more 

 familiar with the species. If a determination is made bj^ means of * 



