4,42 Mr. R. McLachlan on 
In the tenth edition of the ‘Systema Naturze’ (1758), 
we find an insect named Hemerobius formicaleo, still with 
the word “ nebulosis” applied to the wings. 
In the second edition of the ‘Fauna’ (1761), there is 
again a Hemerohius formicaleo, but there is here no men- 
tion of the nebulose or spotted wings; these members 
are simply said to be ‘hyaline, venis fuscis reticulate. 
Finally, in the twelfth edition of the ‘Systema’ (1767), 
the name is changed to Myrmeleon formicarium, and there 
is a very significant modification of the description, the 
words now being “ale nostratis absque maculis fuscis,” 
making it evident that the Swedish insect had immaculate 
wings, whereas he had seen individuals from other quar- 
ters with spotted wings, or, at any rate, was made ac- 
quainted with such by the works of contemporary authors. 
The modern Swedish entomologists* affirm that one 
species only of Myrmeleon occurs in their country, that 
with the immaculate wings, hence the formicarium of the 
twelfth edition of the ‘Systema,’ and the formicaleo of 
the second edition of the ‘ Fauna.’ 
Linné cites the works of Réaumur, Vallisnieri, Roesel, 
Sulzer, Schiffer (‘Hlementa’), Poda, and Geoffroy, and 
all these authors describe or figure the spotted-winged 
species, excepting Schiiffer, who distinctly figures that 
with immaculate wings. 
How then did he come to describe the insect, as with 
markings on the wings in his earlier works;? and this 
question is more especially directed to the first edition of 
the ‘Fauna.’ I hazard a conjecture. It is well known 
that the perfect insects of Myrmeleon are rarely seen at 
large in a state of nature, they being nocturnal in their 
habits, concealing themselves adroitly during the day. 
On the other hand the larvze, or rather the pit-falls made 
by them, force themselves upon our attention. Hence I 
consider it very probable that Linné, at the time of pub- 
* Wallengren remarks, that he formerly (Ofv. Vet.-Ak. Forhand., 1863) 
erroneously diagnosed the Swedish insect as with spotted wings, and that 
Thomson made the same mistake. 
+ In his private, interleaved, copy of the twelfth edition of the ‘ Sys- 
tema’ (in the possession of the Linnean Society), Linné (in MS.) refers 
the immaculatum of De Geer, as a synonym of formicariwm; and Wal- 
lengren likewise includes the name among the synonymy given by him. 
But De Geer’s insect is stated to be from Pennsylvania ; it is a recognisable, 
and common, North American species (cf. Hagen, North American Sy- 
nopsis. p. 231). Gmelin makes the name a synonym of formicalynw, and 
adds ‘America’ as a habitat for that species. 
