OSTEN SACKEN OX WESTERN DIPTERA. 227 



one from jSTew Mexico, and one from the Southern States. Geron occurs 

 everywhere. Two PhtMricc are known from the Atlantic States, one 

 more from Colorado, and three from California. 



The most interesting addition to the North American fauna in this 

 family is Ujnhates, a new genus, the male sex in which is distinguished 

 by a muricate surface of the thoracic dorsum. I have not less than 

 seven species in it, four from the Pacific coast, two from the Atlantic 

 States, and one uncertain. 



As a general result, I will state that the large genera of this family 

 occurring in the United States are universal or nearly universal genera. 



The genera peculiar to the fauna, with the exception of Upibates, are 

 ail as yet monotypical. The genera which do not belong to either of 

 these two categories are: — Ploas, which, besides North America, occurs, 

 as far as I know, only in the fauna of the Mediterranean and Central 

 Asia. It is singular that it has not been recorded from South America. 

 Systropus counts several species in Mexico and South America, also 

 at the Cape, and iu Australia. ToxopJiora occurs in Algiers, Syria, the 

 Cape, Brazil, and Java. Phthiria is found in the Mediterranean region 

 and in Central Asia, at the Cape, also in Brazil and Chili. 



A fact worth noticing is the common occurrence of some species of 

 Bomhylidw iu both hemispheres, or, if the specific identity is contested, 

 at least the great resemblance between some species in Europe and 

 America. 



The European BomhyVms major seems to be the same as the most 

 common species in California. B. fratellus, from the Atlantic States, 

 is very little different from it. Systoechus vulgaris and Anastoechus 

 harhatiis are remarkably like the European species of the same genera. 

 Anthrax dorcadion n. sp. (= the true A. ca]}ucina F.) is the same, or 

 nearly the same, as the species known as A. capiicina in Europe. 



Of all families of Diptera orthorhapJm, hardly any have been so im- 

 perfectly studied iu their organization as the Bomhylidw. By gradual 

 additions, the number of genera has reached very near seventy, and 

 nevertheless the discrimination of the essential characters on which to 

 base a classification may be said not to have been even begun. Dr. 

 Schiner (No vara, p. 115) proposed a subdivision of the family in four 

 groups, — the Aiithracina, Lomatina, Toxojpliorina, and Bombylina. But, 

 as he did not characterize these groups, this subdivision can have but 

 very little value. It would seem self-evident that any attempt at a sub- 

 division must be preceded by a thorough study of the outward organ- 

 ization of these insects; nevertheless, this has never been done yet. 

 The thick fur, the hairs and scales, which cover the whole body, or cer- 

 tain parts of it, render such a study difficult, unless that covering is 

 removed ; and many an important character may have been overlooked, 

 owing to the neglect of undergoing that trouble. As an instance of 

 such an oversight, I will mention the remarkable epimeral hooks which 

 exist in most of the genera of the Anthracina above the root of the 



