110 HORSE AND CATTLE FLIES. 
published in 1845,* embodying his own minute observations of 
organisation, and more especially visceral organisation, of the Pupipara 
as especially studied by him in the Hippobosca equina (Forest Fly), the 
Melophagus ovinus (Sheep Tick or Spider Fly), and also the Ornithomyta 
viridis (Bird Spider Fly). In the latter part of this treatise (pp. 73- 
93) M. Dufour enters on minute detail of structure and embryological 
conditions relatively to method of propagation, which he considered to 
prove that from the first dawn of existence neither egg nor larva was 
to be found, but that the early development and method of nutrition 
resembled that of the Mammalia. Therefore he considered that, 
instead of the usual entomological terms for the stages of life preceding 
the pupal states, it would be more correct to use the words ‘‘ embryo” 
and “ fcetus.” 
This view of development attracted great attention at the time, and 
likewise contradiction ; but those who care to go into the subject will 
find much of what may be called useful straightforward information 
regarding both external and internal structure of the three species of 
Pupipara above referred to, in the earlier pages of the treatise. And 
to those who care to study his minute embryological descriptions, 
accompanying them with perusal of Leuckart’s quarto as a commentary 
on the points in which he considered Dufour was in error,—and also 
how in the main point on which Dufour based his view of mammalian 
development this eminent entomologist was correct as to what he saw, 
but wrong in what he considered the structure to be,—the study of 
the latter part of the treatise will be of considerable interest. 
From the interest that was excited temporarily in this country 
regarding the habits of the Forest Fly, attention was directed to it 
(very much through correspondence published in our journals the 
‘Field’ and the ‘ Veterinary Record’) elsewhere, of which some notes 
may be of use in connection with what may be called ‘‘our own” 
species in other countries, or species belonging to other countries, of 
which one kind at least, the H. canina, especially infesting dogs, and 
found in some parts of Europe, may possibly (if attention was directed 
to the subject) be found present with us. 
Hipproposca EQUINA IN THE Canary Istanps.—On the 29th of August 
I was favoured by Mr. A. H. Bechérvaise, writing from Santa Cruz, 
Teneriffe, Canary Islands, with the following letter, specimens being 
despatched accompanying :—‘‘ Having read your letter in the ‘ Field’ 
of the 10th inst., I am sending you to-day a small box containing some 
* «Etudes anatomiques et physiologiques sur les Insectes Diptéres de la famille 
des Pupipares,’ par M. Léon Dufour (‘ Annales des Sciences Naturelles,’ 3 me Ser, 
tome iii., Janvier, 1845.) 
