@ P21 +) 
VIII. On the Frenulum of the Lepidoptera. By 
GEORGE CHARLES GRIFFITHS, F.Z.S., ¥.E.S. 
[Read October 6th, 1897.] 
PrarE TV. 
THE existence of an apparatus for connecting the fore- 
and hindwings of many of the Lepidoptera was _ first 
noticed by the Swedish naturalist, De Geer, in the first 
volume of his “Mémoires pour servir 4 lHistoire des 
Insectes,” published in 1752. He there describes “a 
process curved like a hook, situated on the under surface 
of the forewing near its base, which holds with its point 
a long stiff hair springing from the basal portion of the 
hindwing.” This, he says, he has found in the males of 
all species of nocturnal Lepidoptera in which he has 
sought it, but not in any of the Diurni. He failed, how- 
-ever, to detect the corresponding appliance in the females, 
and in summing up his account of the organ candidly 
owns himself to be ignorant of its use, though he seems 
to have recognised that it has the effect of making the 
fore- and hindwings act in unison. 
The next mention of the appliance occurs in an essay 
on the “Tendons and Membranes of the Wings of 
Butterflies” by Moses Harris, 1767. The author figures 
and describes the spring or bristle and observes that. it 
pertains only to the males, the females having instead of 
the spring four small hairs or bristles. 
On the 2nd June, 1789, a paper entitled an “ Account 
of a singular conformation in the wings of some species 
of moths,” by Esprit Giorna of Turin, was read before 
the Linnean Society and published in its Transactions, 
i, p. 135. 
The author was unaware of De Geer’s previous refer- 
ence to the subject, and lays claim to the discovery of the 
appliance. To this he is, in fact, partially entitled, as he 
supplements the research of the earlier observers by call- 
ing attention to the corresponding apparatus to be found 
in the females of many species. He gives a list of some 
TRANS. ENT. SOC. LOND. 1898.—PART II. (JUNE.) Y 
