DIRECT INJURIES CAUSED BY INSECTS. 87 



latter genus, while it bears a striking resemblance to the 

 former. It is not clear whether his draughtsman meant 

 to represent the insect with six or with eight legs : if it 

 had only six, it was probably a Pediculus ; but if it had 

 eight, it would form a new genus between the Acaridce 

 and the hexapod Aptera. Dr. Bateman, in reply to some 

 queries put to him, at my request, by our common and 

 lamented friend Dr. Reeve, relates that he understood 

 from Dr. Willan, in conversation, that the insect in ques- 

 tion jumped in its motion. This circumstance he regards 

 as conclusive against its being a Pediculus ; but such a 

 i consequence does not necessarily follow, since it not sel- 

 dom happens that insects of the same genus either have 

 or have not this faculty ; for instance, Cyphon hemisphce- 

 ricus, Acarus Scabiei, &c. 



Dr. Willan has quoted with approbation two cases from 

 Amatus Lusitanus, which he seems to think correctly de- 

 scribed as Phthiriasis. In one of them, however, which 

 terminated fatally, the circumstances seem rather hyper- 

 bolically stated — I mean, where it is said that two black 

 servants had no other employment than carrying baskets 

 full of these insects to the sea ! ! Perhaps you will think 

 I draw largely upon your credulity if I call upon you to 

 believe this ; I shall therefore leave you to act as you 

 please. — Thus much for pure Phthiriasis, which term 

 ought to be confined to maladies produced by lice. I 

 shall only further observe, that as many species as exist 

 of these, which are the causes of disease, so many kinds 

 of Phthiriasis will there be. 



Apart, or mites, are the next insect sources of disease 

 in the human species, and that not of one, but probably 



