( 192 ) 



VI. — On Gnats' Scales. By Jabez PIogg, Esq., Hon, Sec. E.M.S. 



It is said that history repeats itself decennially : if this be a truth 

 in the progress of nations, it appears to be scarcely less true with 

 regard to science, whicli not unfrequently furnishes to the pages of 

 our periodical literature an old discovery furbished up in so attrac- 

 tive a dress that it sometimes passes as a newly-recorded fact. This 

 is certainly the case with a supposed discovery referred to at page 

 1 02 of the August number of the ' Microscopical Journal.' The 

 writer mentions that "in the spring of 1868, while engaged in 

 examining the head of a gnat, he was surprised to discover that 

 the proboscis and palpi were clothed with scales entirely like those 

 of butterflies." The paper on this subject appears in a German 

 scientific journal, " under the joint authorship of Dr. E. Muller 

 and Professor F. Delpino," and it has been translated for the 

 ' American Naturalist ' by Mr. E. L. Packard, a gentleman well 

 acquainted with the Natural History world, who therefore should 

 have known that there was nothing novel in placing on record 

 observations which appeared in my book on the Microscope pub- 

 lished in 1854, and repeated in all subsequent editions, some 

 60,000 copies of which have made their way to every part of the 

 civilized world. A drawing of the proboscis, clothed with scales, 

 is given page 287 Jirst edition, 599 of the sixth edition ; a 

 single scale detached is seen near it; and again, at page 611, 

 another scale, more highly magnified, and exhibiting the " wavy 

 ajjpearance " spoken of by the German authors, but which curiously 

 enough does not quite accurately represent the structural charac- 

 teristics of the scale. The waviness is owing to the under surface 

 being seen rather out of focus. I stated, however, that "the 

 curiously-formed j)robosci8 is covered with feathers or scales ; " and 

 in the woodcut a scale is placed side by side with other test-scales 

 from Lepidoptera and Spring-tails, in order that their structural 

 similarity might be noticed. It is not perhaps so very surprising, 

 after all, that this fact should have escaped the observation of 

 German authors, since it has received so little recognition from 

 English writers on either entomology or microscopy. So far as I 

 have been able to ascertain, no one has described this peculiarity of 



DESCKIPTION OF PLATE CI. 



Fig. 1. — Battledore scale from proboscis of Ctilex pipiens. 



„ 2. — Flattened out scales from body. 



„ 3. — Pointed scale from margin of wing. 



„ 4. — Trumpet scale from thorax, each x 350 diameters. 



„ 5. — Portion of leg and foot. 



„ 6. — Clotlied proboscis. 



„ 7. — Arrangement of scales on wing. 



„ 8. — Scale, Culex ■ , variety unknown. 



