154 Rev. Leonard Jenyns’s Description of the 
narum .* Of the correctness of this opinion, and moreover of the 
identity of my own specimens with those figured by Swammerdam, 
I have but little doubt. Whether Meigen is right in referring De 
Geer’s species to the Masca canicularis of Linnaeus, •j' the Antho- 
myia canicularis of his own work, J I leave to be determined by 
others. I shall however annex an accurate description of the 
larvae in my possession, which will afford the best means of lead- 
ing hereafter to the detection of the particular species, which in 
the present instance at least became an inmate of the human in- 
testines. And even supposing this point to be determined, it may 
still be valuable from the circumstance of that great variety of 
structure which appears to prevail in the larvas of the Diptera, 
and the increased interest taken at the present day in the first 
stage of metamorphosis of insects in general. 
Length, 4-g lines; greatest breadth, line; colour, uniform 
ochreous yellow ; general form, oval, considerably elongated an- 
teriorly, much depressed, especially the head and thorax, which 
are nearly flat ; body, composed of twelve membranaceous seg- 
ments, of which, however, only eleven are obvious. 
First apparent segment of a somewhat indeterminate shape, 
square, approaching triangular, the sides not being exactly paral- 
lel, and its width least at the extremity, which is bounded by a 
straight line. No antennae or eyes ; but in the middle of each 
side a projecting coronet of minute air tubes, arranged in a semi- 
circular form, which might easily be mistaken for the latter. § 
In front is a simple opening, showing externally, in its quiescent 
state, only a pair of minute appendages resembling palpi ; within, 
however, it is furnished with a protractile process, being the head, 
terminating in a pair of horny bristles, representing the mandibles. 
This process is distinctly visible through the integuments, appear- 
ing as a black streak, and is probably capable of being exserted 
considerably beyond the mouth. 
Second segment in form resembling the first, excepting that the 
sides, which are anteriorly inclined to each other, as in that seg- 
ment, alter their direction about the middle of their course, and 
become parallel. The length and greatest breadth of this segment 
* Bibl. Sat. tab. 38, figs. 3 and 4. 
t Syst. Nat. (edit. 12), tom. i. p. 992, 80. 
| Zweijhig. Ins. v. p. 143. [Bouche ( Naturgesch. der Insect, p. 89, pi. vi. fig. 3,) 
has figured the larva of Anthomyia ( Homalomyia ) canicularis of Meigen, and his 
figures, making allowance for their acknowledged rudeness, evidently represent 
these larvae. — J. O. W.] 
$ Evidently considered as such by Dr. Bateman, who appears also to have 
regarded the first pair of branchial-like appendages as antennas. 
