PNEUMONYSSUS GRIFFITHI 687 



The gamasids belonging to the genus Ptilonyssus are parasitic on 

 passerine birds, and at least one species is found on the common sparrow ; 

 they are very similar to Pteroptus, but the abdomen is longer and is 

 separated by a constriction from the cephalothorax. Several species of 

 Liponyssus are known from mice and bats ; they are very similar to 

 Dermanyssus, but are of a lighter colour. The species belonging to the 

 genera Halarachne are very little known ; one species has been found in 

 the bronchial passages of seals ; it is elongated and looks like a miniature 

 tick ; the mandibles are divided pincer-fashion. 



GENUS PNEUMONYSSUS 



The mites of this genus are parasitic and blood-sucking, and inhabit 

 the bronchi and lungs of monkeys. Pneumonyssus simicola, which 

 appears to be the type species, was found in the lung of a Javanese 

 monkey. Two new species, described in 1906 by Newstead, and placed 

 in this genus, appear to differ considerably from the type, and it is 

 possible that a new genus will have to be created for their reception. 

 Both of these species possess a dorsal scutum, whereas the absence of 

 this character is, according to Banks, the distinguishing feature between 

 this genus and Halarachne (see above). 



The following key will serve to distinguish the three species : 



1. Dorsal shield absent simicola. 



Dorsal shield present ........... 2 



2. Palp of three equal joints, the basal one twice as broad as the 



apical duttoni 



Palp four jointed, segments subequal ..... griff ithi 



Pneumonyssus duttoni, Newstead, was found in the tracheae and 

 bronchial passages of an African monkey, Cercopithicus schmitdi, in the 

 Congo district. Only the adult females and the larvae were found, 

 males being entirely absent. The females occur in the trachea and its 

 first four or five subdivisions, the larvae mainly in the smaller bronchi. 

 No symptoms are ascribed to their presence, except perhaps for a slight 

 bronchitis. Eggs were not found. 



Pneumonyssus griffithi, Newstead, is recorded from the lung of the 

 Indian monkey, Macacus rhesus. Unlike the preceding species, it 

 appears to produce definite pathological changes in the lung. In the 

 infected animals a series of six the lungs showed numerous small 

 cavities chiefly situated under the pleura, and varying in size from half to 

 one millimetre in diameter. Each cavity is continuous with a small 

 bronchus, and has a thin fibrous wall, lined internally by silvery white 



