578 MODERN CLASSIFICATION OF INSECTS. 
larva not exactly agreeing with any of the known species of Cistri- 
deous: larvee, and which Dr. Brick had himself extracted from a tu- 
mour in his thigh. Mr. E. Doubleday, whose recent Entomological 
tour in America has added such stores of novelties to our museums, 
has informed me that he suffered from the presence of a larva in 
the calf of one of his legs, which unfortunately he destroyed. M. 
Goudot, the Entomologist, whilst travelling in America, was also si- 
milarly attacked. Mr. Howship has also described two cases observed 
in South America, in one of which the larva was found in the back, 
and in the other in the scrotum.* He has also published a figure of one 
of these larvae. A similar case to the last has also been recorded by 
M. Roulin, and M. Guérin has also communicated another case from 
Martinique to the Académie des Sciences, upon which M. I. G. Saint 
Hilaire has published a report in the Ann. Soc. Ent. de France, 1833, 
p- 518., and see also a notice by M. V. Audouin of an additional case 
in the same volume, App. p. 65. Likewise the Mag. of Nat.. Hist, No. 
27., and Arture’s Mémoire sur [ Espéce de Ver nommé Macaque. 
The larve of the Céstridz are, in general, thick fleshy grubs, some- 
what attenuated towards the head, not furnished with legs. Their body 
is composed of 11 segments, exclusive of the head; furnished with 
minute tubercles and spines, the latter often arranged in rows, which 
facilitate their progression, and are the cause of great irritation to the 
animals upon which they are parasitic. The chief respiratory organs 
are placed upon a scaly plate at the posterior extremity of the body, 
which is thicker than the anterior. It would seem that the mouth of 
the cutaneous larvee is composed only of fleshy tubercles, whilst that 
of the cervical and gastric species is always furnished with two strong 
unguiform appendages. How far these larvee (which subsist on the 
purulent humours secreted by the animals on which they are para- 
sitic, and originating in the irritation produced by their presence) are 
really detrimental to the animals on which they are parasitic, is a mat- 
ter of controversy. Mr. B. Clark, whose long experience in veterinary 
matters gives great weight to his opinion, maintains that they are 
rather beneficial than otherwise ; a contrary opinion has been main- 
tained by Mr. Sells, in a memoir on these insects presented to the 
Entomological Society, as well as by some other authors. (See Kollar, 
Obnox. Ins. Translat.) The pupa state is passed under ground, the 
* « Some account of two cases of inflammatory tumour produced by (Estrus 
humanus.” 
