2 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
till the present year they have described only nine species. Aldrich's 
Catalogue of Xoi'th American Diptera lists twenty-four species as 
definitely reported from the United States, but aside from the nine 
above noted these were described by Walker, Macquart, and other 
of the older European entomologists. 
Much of the recent work in Europe has been based on genitalia as 
the principal means of identification. Dr. Bottcher's paper ^ on 
Sarcophaga is especially deserving of commendation in this regard, 
and has been of great assistance in preparing this paper. The writer 
fully recognizes the great importance of these characters and figures 
are presented for each species, though in most cases their use is not 
necessary after one has familiarized himself with the external char- 
acters of the group. It is doubtful if our species present the difficulties 
attendant upon the identification of European material, especially 
of those species with black genital segments. An undescribed Ameri- 
can species of Sarcophaga and the European <S. idiginosa Kramer are 
the only two species which cannot be separated on external characters, 
but the examination of the genitalia is highly advisable when speci- 
mens are in any way not typical. 
It has been impossible to examine the types of all the species de- 
scribed by American writers, but those not seen either do not occur 
in New England or there is no question as to their identity. Whenever 
possible the location of types, cotypes, etc., has been given with the 
descriptions of the individual species. 
The possibility that some of the species described as new may have 
previously been named by Walker or others is fully recognized, but 
their descriptions are inadequate and it has been impossible to see the 
types. 
The author wishes to express his appreciation and gratitude to 
Professor H. T. Fernald, not only for the assistance and encouragement 
given, but also for the kindly interest which he has shown during the 
progress of the work, and to Professor G. C. Crampton for his aid and 
suggestions in the preparation of the morphological portion of this 
paper. The terminology of the thoracic sclerites is that used by Dr. 
Crampton, (1914),^ except that the term 'pleurotergites' was first 
1 Bottcher, G. Die mannlichen Begattungswerkzeuge bei dem Genus Sarcophaga 
und ihrc Beudeutung fur die Abgrenzung der Arten. Deutsch. Ent. Zeitschr., 1912-'13. 
- Crampton, G. C. Notes on the thoracic sclerites of winged insects. Ent. News,. 
1914, vol. 2.5, p. 1.5-25, pi. .3. 
