ANTHOMYIA CANICULARIS. 253 



several quarts : they were alive, and continued to be passed for several 

 months. This case is recorded by the Rev. Leonard Jjjnyns, in the 

 ' Transactions of the Entomological Society,' vol. ii, part 3, find is accom- 

 panied by a very accurate figure of the insect. A rather rude drawing 

 of evidently the same insect also accompanies a paper by Dr. Bateman in 

 the seventh volume of the 'Edinburgh Medical and Surgical Journal,' 

 p. 48, on the subject of larvae found in the human body ; while a much 

 older, though more accurate one, will be found in Swammerdam's ' Bibl. 

 Nat.,' tab. 38, figs. 3 and 4. And, lastly, may be mentioned a case pub- 

 lished in the second volume of the ' Memoirs of the Medical Society of 

 London,' which appears to be of a similar kind. These are the only cases 

 that I find recorded of the occurrence of the larva in the human subject, 

 but it has also been observed in the Boa constrictor, as appears from an 

 instance recorded by Mr. Iliff, to which I have just alluded, and where the 

 larvse were passed along with the masses of urate of ammonia, which 

 constitute the excrement of that animal. 



" There appears to be little doubt that in all these cases the insect is 

 the same, and that it is the larva of the Anthomyia canicularis of Meigen, 

 or Musca canicularis of Linnaeus. 



" Its minute anatomy does not appear to have been investigated, and it 

 is this deficiency which I shall attempt to supply from my notes of the 

 dissection of the specimens obtained from the first case to which I 

 alluded. 1 



" The larva is five lines in length by one and a half in breadth. It is of 

 a dull-brown or blackish-brown colour, soft and flexible, but having a tough 

 integument, which, however, is sufficiently transparent to allow of the ali- 

 mentary canal being seen through it. The body consists of eleven segments, 

 but the last is apparently formed of three blended into one. Each segment 

 carries a pair of feathery branchial appendages, which project at right angles 

 from the body, constituting a double row on either side. There is also a 

 double row of small eminences extending down the dorsal surface, but the 

 abdominal surface is nearly smooth. The lateral appendages, of which the 

 upper series is much larger than the lower, are pinnate. The central shaft 

 of these, which is long and pointed, is hollow, and communicates appa- 

 rently with the tracheae. The lateral pinnae are again pinnated on their 

 outer margin. The integument, which appears smooth to the naked 

 eye, is found, when examined under the microscope, to be granulated 

 all over with minute dentiform or pointed processes, which appear to 

 be of a harder nature than the rest of the tegument, and resemble on 

 a small scale the spinous prominences in the tegument of certain carti- 

 laginous fishes, as the sturgeon ; and it appears to be only an extra- 

 ordinary development of these latter processes which constitutes the 

 long feathery lateral appendages already described. 



" The mouth of this larva is perhaps the most interesting part of 

 its anatomy. The head is furnished with two broad fleshy lips, which 

 together constitute a broad disc, having in its centre a minute aperture 

 leading to the oesophagus, and flanked on either side by the hook-shaped 

 mandibles, the sharp points of which are directed downwards and some- 

 what outwards, and are nearly retracted each within a separate sheath, the 



1 For a specimen of this larva consult the Museum of the Royal College of Surgeons, 

 London ; Cat. Nat. Hist. Series,' part iv, No. 609, D. 



