ANTHOMYCIDA. 95 



has a brown spot, consisting of nothing but points. 0n the flat- 

 tened part of the tail, we see two very small, broadly oval, 

 oblique, dark reddish-brown opercula, much smaller than in 

 (Eatrus Ovis ; these close the two main tracheae from without. 

 The surface of the opercula is veined and finely punctured. 

 Beneath the opercula is the opening of the intestine, which, like 

 the alimentary canal and stomach, is situated, as in the other 

 (Estri, in the centre between the tracheae. The eggs of par- 

 ticular species of (Estrus have opercula. 



Sheep, cattle, and horses are only infected in thickets and 

 woods, where the female (Estri sit, and attack the passing animals. 

 This is not to be overlooked in the etiology and prophylaxis. 



Family of the Flies = MUSCIDA. 



From the enormous number of genera (200) we must be con- 

 tented with having the characters of the Brachycera before us, and 

 to state the distinctions of the particular genera. For us par- 

 ticular interest attaches to the flower-flies = Anthomycida, and 

 the flesh-flies =Calyptera or Creophila. 



1. Anthomycida = Flower-Flies. 



Squamce sive ailerons (== alulets) halteribus multo minor -es. 

 Antennas retro repositce tertio articulo oblongo. Oculi fere frontales, 

 in maribus propinquiores. Corpus longum. Caput hemispharicum. 

 Larvae 2 unguicules ad os armata, in vegetabilibus putrescentibus 

 viventeSj sine pedibus. 



We know that larvse of Anthomyia scalaris and canicularis 

 have been met with in the human intestine. They may be 

 recognised by their maggot-like form, by the plumose lateral 

 and dorsal spines, and the two separated, stalked breathing tubes 

 on the last segment of the body. The spinous bristles on the 

 back and sides are said to produce a very unpleasant itching in 

 the human rectum. I advise surgeons, in order to obtain speci- 

 mens of this larva, so as to be able to know what they are about 

 in case of need, to look after the larvse in the intestines of dogs, 

 where they occur by no means rarely in autumn and winter. 

 Upon the literature of this subject consult Von Siebold, article 



