SUBFAMILY DERMANYSSINAE 685 



fluid, the excretion of the Malpighian tubes. The tubes begin blindly in 



the neighbourhood of the mouth parts and pass back- 



,,,.,.. . Hind-intestine, rectum 



wards below the mid-mtestme, to end on the posterior and Malpighian tubes 



surface of the rectum ; as in ticks they come in contact 

 with most of the organs. 



The salivary glands lie on each side of the anterior end of the body ; 

 each gland is elongated and broadest at its posterior end. It consists of 



a number of acini lined by large granular cells, which 



i u i 11 A I ( ^ i u i Salivary Glands 



form lobules ; small ducts pass from the lobules and 



enter the main salivary duct, which enters the buccal cavity at its 

 posterior end ; accessory glands are also present. 



In many of the aberrant forms some of the organs described above are 

 not fully formed. The reproductive organs are very similar to those of 

 ticks and do not call for any separate description. 



The Gamasidae have been classified in many different ways' by differ- 

 ent authorities, and, as in the case of ticks, the tendency has been to raise 

 them to the level of a superfamily, as the Gamasoidae (Banks), dividing 

 this into several families. In the following the classification of Banks is 

 followed, the group being however regarded as a family, and his families 

 as subfamilies. 



Subfamilies of Gamasoidae (after Banks) 



1. Parasitic on vertebrates; mandibles fitted for piercing ; body 



sometimes constricted ........ Dermanys.sinae. 



Free, or attached to insects (rarely on vertebrates, never on 



birds) 2 



2. First pair of legs within the same body opening (camerostoma) 



as the oral tube ; dorsum of body projects beyond the 

 camerostome ; genital aperture surrounded by the sternum. Uropodinae. 

 First pair of legs inserted at one side of the mouth opening ; 

 dorsal surface of body does not project in front of the 

 camerostome ; male genital aperture usually on the anterior 

 margin of sternal plate (sometimes in the middle) , . Qamasinae. 



SUBFAMILY DERMANYSSINAE 



The distinctions between the Dermanyssinae and the Gamasinae are 

 by no means well marked, as many of the forms are very similar in struc- 

 ture and merge into each other ; most of the Dermanyssinae, however, 

 are parasitic, and this seems to be the main distinction between the two 

 subfamilies. Banks arranges the important genera as follows : 



BANK'S KEY TO THE GENERA OF DERMANYSSINAE 



1. Anal plate present 2 



Anal plate absent , r ..... . . . . -.-, , . . . .5 



