10 THE ENTOMOLOGIST. 



generally laid down as distinctive of Lepidoptera ? I thought 

 that the character in question was absolute, and I wish to 

 know whether these statements of microscopists are reliaVjle, 

 more particularly as I have caught several gnats for the 

 purpose of investigating the subject, and have always failed 

 to discover the scales in question. — Edward Wright. 



The statement is pe4fectly true, and is familiar to structural 

 or anatomical entomologists, although it seems to have been 

 forgotten or lost sight of from time to time, until some 

 microscopist reproduces it every few years, when it crops 

 up as a new discovery. It is nothing more than a conven- 

 tional idea, or sometimes a convenient assumption, that the 

 scales in question are confined to Lepidoptera, and the 

 assumption is utilized now and then to set up some hobby, 

 such, for instance, as the Lepidopterous nature of Acentria, 

 which assumption remains standing only until some one of 

 more extended or more careful powers of observation, or 

 more skilled in logical deductions, knocks it down again. 

 Meigen is the first author I recollect who distinctly mentions 

 the presence of scales on the wings of Diptera, and this as 

 early as 1804; but the subject has been thoroughly investigated 

 by Mr. Hogg, the able Secretary of the Microscopical Society, 

 in his work on the microscope, first published in 1854, and 

 repeated in subsequent editions. The paper which has 

 recently revived the subject appears in a German scientific 

 journal, under the joint authorship of Dr. E. Miiller and 

 Professor F. Delpino, and was translated for the ' American 

 Naturalist,' by Mr. R. L. Packard, a gentleman well 

 acquainted with the natural-history world, and one who 

 should have known that there was nothing novel in these 

 observations. A drawing of the proboscis clothed with 

 scales is given at p. 287 of Mr. Hogg's first edition, and in 

 the following four editions ; at p. 599 in the sixth edition ; a 

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

 another scale more highly magnified, and exhibiting a wavy 

 appearance, which is noticed by the German authors, but 

 which, curiously enough, does not quite accurately represent 

 the structural character of the scale. The waviness is owing 

 to the under surface being slightly out of focus. It is not, 

 perhaps, so very surprising that this fact should have escaped 

 the observation of German authors, since it has received so 



