THE ANNALS 
MAGAZINE OF NATURAL HISTORY. 
[THIRD SERIES. ] 
No. 105. SEPTEMBER 1866. 
XXIV.—WNotes on some Species of the Orthopterous Genus Cloéon, 
Leach (as limited by M. Pictet). By A. E. Eaton, of Trin. 
Coll. Camb. 
AttHoucH but little attention is paid by the generality of ento- 
mologists to the Ephemeride, the following notes may prove not 
altogether uninteresting. From reading Dr. Hagen’s introduc- 
tory remarks to his synopsis of the British species of this family 
(Ent. Ann. 1863) one might be led to imagine that in their early 
stages of development they are strictly carnivorous. The exist- 
ence of such a propensity is clearly seen by merely placing a 
number of pup in a small vessel, when the stronger will speedily 
devour such as they are able to master. But that their diet is 
partly vegetable also is apparent on an examination of the con- 
tents of their alimentary canal ; for, in many instances, along 
with a large proportion of mud, half-digested Diatoms and 
pieces of Confervee can be detected. These the animals obtain 
by nibbling over the surface of water-plants and stones—an oc- 
cupation to which they are much given. For this work their 
jaws are admirably suited. In the front are four or five strong 
sharp teeth, arranged in two rows, whilst behind these is a very 
singular structure—a flattened transversely striated protuber- 
ance, somewhat resembling an elephant’s tooth im miniature*. 
Their subulate antenne and their unconcentrated abdomen are 
not the only points in which they resemble Libellulide, as, be- 
sides the branchial plates of the pupa, the rectum is subservient 
to purposes of respiration. They seem to be furnished with a 
muscular cloaca, which is shut off from the extremity of the ali- 
mentary canal by a voluntary sphincter muscle. Its external 
aperture is the anus, through which water is admitted when the 
insect wishes to inspire. The cloaca being filled, this is then 
‘closed, the rectum opens, the cloaca contracts and forces the 
* Jaw of the pupa of Ephemera vulgata, L. 
Ann. & Mag. N. Mist. Ser. 3. Vol. xviii. 1] 
