384 CALIFORNIA ACADEMY OF SCIENCES. 



The genus Probosca accordingly disappears from our 

 lists. On the other hand I have found it necessary to 

 add two other European genera: Sparedrus and Chry- 

 santhia, the former to include Calopus asftersus and prob- 

 ably many if not all those described from Mexico by Mr. 

 Champion, the latter a new species which so closely 

 resembles thoracica as to be not easily separated from it. 



The genus Microtonus has also given rise to the sug- 

 gestion of Mr. Champion that it should probably be re- 

 ferred to the Melandryidee. While I agree with him that 

 the genus seems here out of place, a discussion of the 

 question would involve the validity of several entire 

 families. The Melandryidae, Pythidre (including Myc- 

 terus, etc.) and OEdemeridee are by no means well de- 

 fined, as I some years ago intimated in a brief study of 

 the first of these families. 



For the present it will be better, as Mr. Champion sug- 

 gests, to allow Microtonus to remain in the position in 

 which it was placed by LeConte, until such time as the 

 species referred to it by Champion, as well as some Sym- 

 phora (to which it seems allied), can be more closely 

 studied. 



The genera at present known in our fauna may be 

 separated as follows: — 



Eyes deeply emarginate. 

 Penultimate tarsal joint alone dilated. Calopus. 



Penultimate and the preceding dilated. Sparedrus. 



Eyes feebly emarginate or entire. 



Penultimate joint of tarsi narrowly dilated. Microtonus. 



Penultimate joint of tarsi broadly dilated. 2. 



2. — Anterior tibia? with a single spur; antenna? 12-jointed S , 



11 -jointed?, 3. 



Anterior tibiae with two spurs. 4. 



3. — Eyes scarcely emarginate. Nacerdes. 



Eyes moderately deeply emarginate. Xanthochroa. 



4. — Tarsi with several joints spongy-pubescent beneath; body stout. 



Ditylus. 



