Vol. 5, p. 47-50. October 31, 1922. 



Occasional Papers 



OF THE 



Boston Society of Natural History. 



NOTES ON CLUSIODIDAE (DIPTERA). 



BY JOHN R. MALLOCH. 



Since the appearance of my revision of this family in the Pro- 

 ceedings of the Entomological Society of Washington, in 1918, 

 I have collected many more specimens and have elucidated some 

 points that necessitate the publication of additional notes on two 

 genera. 



The generic characters used in the family are rather trivial in 

 some cases and a strict application of these throughout the group 

 would result in the erection of several more genera> a course which 

 seems to me inadvisable in a group as homogeneous as this. I 

 present a key to the species of the genus Clusiodes known to me 

 to occur in the eastern United States and indicate characters for 

 the subdivision of the genus into three subgenera. 



The type specimens of the species taken by Mr. C. W. Johnson 

 are in the collection of the Boston Society of Natural History. 



Key to Subgenera and Species of Clusiodes. 



1. Postvertical bristles present 2. 



Post vertical bristles absent (Subgenus Columbiella) 15. 



2. Thorax with three long strong pairs of dorso-central bristles, the anterior 



pair in front of suture (Subgenus Clusiodes Coq.) 3. 



Thorax with two strong pairs of dorso-centrals and usually one or two 

 pairs of weak setulae behind suture (Subgenus Clusiaria) 4. 



3. Anterior margin of mesonotum black between the humeri; each orbit with 



three bristles, the upper one weak; fore metatarsus black; palpi black 



apically albimana Meigen. 



Anterior margin of mesonotum between humeri yellow; each orbit with 

 two bristles, the upper one absent; fore metatarsus black, white at tip; 

 palpi black americana, sp. n. 



4. Males 5. 



Females 10. 



5. Two very long strong vibrissae on each side of mouth; face and cheeks 



almost entirely black; each orbit with two bristles duplicata, sp. n. 



Only one strong vibrissa on each side of mouth; each orbit with three 

 bristles, the upper one weak 6. 



6. Face deep black except below antennae, cheeks blackened anteriorly; 



upper orbital bristle very weak and yellow; dorsum of thorax rufous 



melanostoma Loew. 



Face not deep black; upper orbital of moderate strength, black 7. 



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