52 



gether he must have passed several quarts : they were alive, and con- 

 tinued to be passed for several months. This case is recorded by the 

 Rev. Leonard Jenyns, in the 'Transactions of the Entomological 

 Society,' vol. ii. part 3, and is accompanied 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 & 4. And lastly may be mentioned a case published in the 

 2nd 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 sub- 

 ject, 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 larvae 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.* 



The larva (PI. v. fig. 1, d) 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 alimentary canal being seen through it. 

 The body consists of eleven segments, but the last is apparently 

 formed of three blended into one, (figs. 2 & 3). Each segment car- 

 ries 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, (fig. 4), 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 apparently with the tracheae. 

 The lateral pinnae are again pinnated on their outer margin. The 



* For a specimen of this larva consult the Museum of the Royal College of Sur- 

 geons, London ; Cat. Nat. Hist. Series, pt. iv. No. 609, D. 



