THE 



PHILOSOPHICAL magazine. 



I. Some original Remarks on a Variety of the Genus AcaruSy 

 leloiig')n<r to the Order Aptera, found on the tVings, ^c. 

 of a feathered Fly of tlie Order D'lptera. By Mr. Joa J} 

 Snart, Optician. 



To the Editor of the Philosophical Magazine. 



SIR, 



X SHOULD not have thought myself very well employed in 

 writing the following particulars of so trivial a creature as 

 I am about to treat of, were it not with the view of drawing 

 some new inferences, and even an unequivocal line of de- 

 marcation between animalcula that are of a perfect gene- 

 ration and those which are not so, although they are 

 often indiscriminately blended : and though I will not per- 

 emptorily dare to dogmatically assert that the one in ques- 

 tion is the ne plus ultra of nature's perfect beings, in a small 

 way ; yet it is the utmost boundary I have seen, or evea 

 read of in those entomological writers who have criven 

 simple statements of facts only. I do not mean to include 

 the animalcula infusoria in this idea; for it is plain that 

 nature's manner of perpetuating a species by mere vegetative 

 impregnation is essentially different and distinct from sex- 

 ual intercourse, or copulation ; although it may be urged by 

 some (what I think is very doubtful), that the germ or ova 

 of the former is always shed or ejected in the water, &rc, 

 beforehand : but as the common pediculus, or louse, it is 

 evident, is originally formed from the exudation of the 

 skin, which vegetates, becomes vascular, organizes, and 

 lastly animates, and assumes loco-motion (without a fa- 

 ther, and is xhextiovo. sui generis) , this also may be the 

 case with the creature of which I am writing, which mav 

 originally be produced in this way, as well as many others ; 

 but after they have attained the capacity of propagating their 

 species per sr, provident nature, whose characteristics are 

 smiplicity anil o^conomy, and who never makes use of two 

 sorts of means where one will answer the intended end, 

 may leave them to shift for themselves when capable. As we 

 take away the leading-strings when the child can walk 

 Vol. 23. No. Sy. Oct. 1803. A 2 alone; 



