2 PROCEEDINGS OF THE NATIONAL MUSEUM art. 11 



Fucomyia had originally three species — the first was what Haliday 

 thought to be the true fngida of Fabricius, which he distinguished 

 from the frigida of Meigen ; of the former he makes his own gravis 

 1833 a synonym. The other two species included are simplex and 

 jKirvida, both new. Westwood (1840, p. 144) makes frigida Fabri- 

 cius the genotype of Fucomyia. But here, again, is a misidentifi- 

 cation of frigida., which is not a Coelopa at all, but probably a 

 Scatophaga (Stenhammar, Copyromyz., 1855, p. 269). Haliday's 

 supposed frigida Fabricius is disposed of by adopting grams 

 Haliday, 1833 for it, since Haliday himself indicated the synonymy. 

 Thus gravis Haliday becomes the genotype of Fucomyia. The ques- 

 tion is not of prime importance, since Fucomyia is undoubtedly a 

 synonym of Coelopa. Fucomyia has bristlj^^ legs, while in Goelopa 

 they are pilose ; but this applies only to males, and is best developed 

 in the large males, smaller ones showing much less difference, and 

 females showing hardly a specific difference, much less a generic one. 



The genus Coelopa is the main component of the small acalyptrate 

 family Coelopidae, which is distinguished by the following characters 

 in Hendei's recent key to the families of Diptera.^ 



Body depressed, postverticals well developed, convergent or 

 crossed ; prelabrum protruding ; tibiae with preapical bristle on dor- 

 sal side, but with apicals only on ventral side ; scutelium with a pair 

 of erect, crossed apical bristles, curving forward; auxiliary vein 

 complete, costa not broken or interrupted at tip of auxiliary or 

 before it. 



In Coelopa the face in profile is very deeply hollowed ; the sides of 

 the epistoma are bulging ; the anal vein reaches the margin, but only 

 as a fold. The mesonotum is strikingly flattened, with no bristh=s 

 of considerable size except a single humeral, two notopleurals and 

 one postalar — of these the single, large erect humeral is most dis- 

 tinctive. The antennae are rather small, the third joint rounded, 

 with bare arista. 



No other genus of the family occurs in North America; in our 

 literature Oinoinyia Coquillett has been referred here, but it appears 

 to show more affinity to the Scatophagidae. 



All of the species vary greatly in size; specimens of vanduzeei^ 

 which are all recognizable by the hairs on the apical portion of the 

 first vein, vary from three to seven millimeters in length. In all 

 cases the larger are more spinose or pilose, the striking vestiture 

 being reduced with the size until it becomes inconspicuous. On this 

 account I have given up parvula as a name for our smaller New 

 England specimens, without attempting to decide whether there is a 



' Tierwelt Deutschlands, Jena, 1928, part 11, section 2, pp. 86-89. 



