14 W. Dzuight Pierce 



Antennae with more than four joints 2 



2. Joints following third simple 3 



Joints following third, not all simple 4 



3. Antennae five-jointed, last two elongate; tarsi apparently 



only two-jointed Elenchus Curtis 



Antennae six-jointed, last three not very much longer 



than third ; tarsi four-jointed Stylops Kirby 



4. Antennae seven- jointed, fourth joint flabellate; tarsi five- 



jointed with two claws (fossil) Triaena Menge 



Antennae seven-jointed, fourth, fifth, and sixth joints 



flabellate; tarsi three-jointed Haliciophagus Dale 



(Myrmecolax, parasitic on ants, and Colacina Westw., parasitic 

 on Homoptera, the author can not locate in default of descrip- 

 tions.) 



Genus Xenos; type X. vcsparum Rossi; August; Europe and 

 America. 



Genus Stylops; type 6\ melitiae Kirby; March 15, May 15; 

 Europe and America. 



Genus Elenchus; type E. tenuicornis Kirby ; June-August ; 

 England, Mauritius. 



Genus Haliciophagus; type H. curtisii Dale; August 15; Eng- 

 land. 



Genus Triaena; type T. tertiaria Menge ; fossil in amber. 



Genus Colacina; type C. insidiator Westw. ; Sarawak. 

 Genus Xenos. 



The genus Xenos is supposed to be found exclusively on wasps, 

 while Stylops is supposed to occur in bees. Hence when a spe- 

 cies of Xenos is taken from a bee it is immediately suspected to 

 be a new species. 



While collecting bees about nine o'clock a.m. on August 10, 

 1903, on the garden squash, Mr. J. C. Crawford, Jr., of West 

 Point, Neb., took a species of Panurginus, in the body of which 

 were two female Xenos, and in his collecting tube, flying fran- 

 tically about, was found a male Xenos. It had probably been in 

 copula with one of the females when taken. 



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