23S 
[March, 
only succeeded in breeding one specimen last June. On May 29th however, I took 
a lo\tly example by beating. I should have announced the capture of this rare 
species befoie, but could not fully satisfy myself about it and delayed submitting my 
specimen to a more competent authority. In the autumn of last year I again met 
ith SLVtial lairff 1 , and hope to see the perfect insect in due course. It seems very 
scaice and local, for though aspen abounds in most of the larger woods hereabouts, 
have only found hostilis in one locality, though I have searched for it well elsewhere. 
At tin end of last September, when beating oak, a considerable number of 
another “ knot-horn ” larva tumbled into my umbrella. These I at first hoped might 
bt Ci yptoblale? bistrigella, but they were so common that it struck me they might 
more probably be young larvae of Rhodophcea consociella, which is abundant in the 
locality , I theiefoie only boxed about a dozen. Some of these were iclineumoned, 
but others became pup* later on, thus proving that they could not be consociella , 
and driving me back to the conclusion that my first impression was most likely 
correct. 
Bistrigella generally turns up here every season, but is always very rare in the 
perfect state. I also met last autumn with Gymnanci/la canella, the larv* of which 
were tenanting several plants of Salsola kali on a retired part of the Essex coast.- 
W. II. Harwood, 8, West Stockwell Street, Colchester: 14 th February, 1881. 
On the Stridulation of Acker ontia.— Dr. Laboulbene takes exception, in the 
“ Annales de la Societe Entomologique de France” (5*»e Serie, t. vii [1877], Bull., 
p. lv), m regard to my failing to quote a paper he had published on the stridulation 
of the Death’s-Head Sphinx, when I, in reply to Mr. Moseley, tried to establish 
the mechanical nature of this sound in the Ent. Mo. Mag., vol. xiii, pp 217— 9*0 
His experience is as follows Eventually I wished to see in what manner the 
animal arranged the fan of hairs lying in the fold. This fold is formed of a dry 
rough skin Ccomme scarieusej, especially at the margin of the first segment where it 
rests on the second. I passed beneath this dry skin the blunt point of a little steel 
rod, and not only did I succeed in thus arranging the hairs, but, to my satisfaction, I 
heard a sound, feeble, but very similar to the cry of the living animal. I repeated 
the same manoeuvre, by pressing on the skin behind the fold and a little higher up 
on the first segment, and every time I caused the hair to fall into its place almost 
invariably I elicited the cry. The reason of this appeared attributable to the 
contraction of the muscles as they shut the fold with its dry membrane, and perhaps 
also to the friction of the rough skin of the first abdominal segment on the second.” 
As the Death’s-Head Sphinx has not been common in this district since the 
autumn of 1878, I have not been able to make further observations on its cry but if 
the true sound can be elicited as Mons. Laboulbene would affirm, I perhaps may 
suggest that I find a much more suitable structure for its production in the hinder 
pieces of the xneso-sternum, which on their inner surface are distinctly limaform.— 
A. H. Swintox, Binfield House, Ghiildford : 3rd February, 1881. 
llcuiciu. 
A Treatise on Comparative Embryology: by Francis M. Balfour 
M.A., F.R.S, Fellow and Lecturer of Trinity College, Cambridge. Svo, 2 volsl 
Vol. I, pp. v— vii, 1—492, and i— xxii. London : Macmillan & Co., 1880. 
An extremely useful summary of what is known on this subject at the present 
time, judiciously arranged and well illustrated with woodcuts. Although Entomo- 
