Ixxiv 



it in considerable numbers over a wide area, and he expressed 

 his opinion that it had been present in this district for many 

 years past. 



A PECULIAR ORGAN OF THE NOTODONTIDAE. — Dr. JORDAN 



showed some Notodontidae and said that in a large number 

 of exotic species of this family the males have on the sides of 

 the abdomen a peculiar organ not met with outside the 

 Notodontids. It is particularly frequent in American genera 

 (Heterocampa, Salluca, Hapigia, etc.). In the species in 

 question the upper margin of the sternite of the fourth segment 

 is widened into a lobe of varying size, the lobe bearing a spine 

 or a bunch of spines at the apex or a regular comb of many 

 spines at the posterior margin. The lobe partly covers a 

 deep cavity, in which evidently opens a gland. The organ is 

 present in all the species in which the scaling on the underside 

 of the hind-wing is modified in some way, but is also found in 

 a number of species with normal scaling. The function of the 

 organ seems to be that of a transmitter of scent from the 

 abdomen to the hairy hind-tibia and hind-wing. An illustrated 

 account of the organ will appear in another place. 



Seasonal changes in the colours of the female 

 BELLARGUS. — Prof. PouLTON said that he had received the 

 following interesting communication from Dr. R. C. L. Perkins, 

 F.R.S. :— 



" September 27, 1922. — I collected a fine series of $ A. 

 bellargus (adonis) in the exact spot where we obtained them 

 last year, i. e. from the same restricted colony (on the 

 Cotswolds) which extends over a few acres of hillside. It 

 was very interesting. Not a single blue $ in last year's lot, 

 but many almost like astrarche (agestis) in colour : this year's 

 females for the most part highly suffused with blue. Owing 

 to the season being later this year, I only had a few hours on 

 two of the last days of our stay, or perhaps I should have 

 taken some like the glorious blue specimens I sent to C. G. 

 Barrett in the excessively wet summer of 1888 or 1889, when 

 the species was only coming out fresh in late September or 

 October." 



Dr. E. A. Cockayne had kindly directed his attention to 

 two papers by Dr. G. G. C. Hodgson, who had also observed 



