SUGAR MITES. 281 



CASE P. D. Murray, that at Sierra Leone there is a native pustular 

 disease called craw-craw, which is a species of itch breaking into 

 open sores, and very troublesome to cure. 



Notwithstanding the imperfection of the materials we cannot 

 feel much doubt that this is a Glyciphagus. It undoubtedly 

 jDelongs either to the Tyroglyphidse or the Sarcoptidae. There is 

 nothing else with which it has even a suspicion of affinity. We 

 cannot place it among the Sarcoptidse, the striated skin being 

 absent, and the legs made on the principle of the Tyroglyphidse. 

 But the presence of the posterior button, so characteristic of the 

 Glyciphidse, seems to us conclusive. So far too as one can judge 

 from I\Ir. Busk's lithographic drawing, which seems uncommonly 

 good, its skin has a velvety structure. In a dead, crushed 

 specimen we should not expect to see the suckers of the tarsi. 

 There remains only the hair on the body to complete the 

 evidence : if they were feathered, there could not be a doubt 

 remaining ; but they are not so figured. We do not, however, 

 regard this as conclusive against the other probabilities. It 

 was only in 1838 that Hering drew attention to this character, 

 and it would not be very surprising if in 1841 and 1842, when 

 there were, no doubt, very few students of Acarids in Eng- 

 land, its value or existence should not be generally known 

 there — and if not known it would be very apt to be overlooked 

 by observers and draftsmen who had paid no special attention 

 to the subject. 



No. 20. Glyciphagus spinipes {Fum. ^ Rob., Journ. Anat. & Pliys. 1867). — 20. 

 Magnified, sketch of ditto, copied from Fum. & Robin's figure. 



Easily distinguished from G. cursor by its smaller size, more 

 conoid form when in life, and by the comparative shortness of its 

 anal appendage ; males and females are nearly equal in size. Its 

 legs are longer, owing to the length of the tarsi, and its hairs 

 are considerably larger and more feathery. It moves with extreme 

 velocity, carrjang one or two of its posterior hairs on each side 



