MELAXOSTOMA. 10 



1 (2) Facial tubercle double, that is, divided 



bv a perpendicular furrow into two 

 small but distinct approximated 

 tubercles; legs and antennae entirely 

 yellow or sometimes more or less 

 darkened ; yellow abdominal mark- 

 ings very extensive, tnose of male 

 sometimes covering the whole abdo- 

 men bituberculatum, Loew. 



2 (1) Facial tubercle simple, or rarely with 



only a trace of a division. 



3 (4) Legs entirely yellow, without dark 



markings ; yellow abdominal spots 

 very broad, rectangular ; larger 

 spocies (8-9 mm.) Jlonpeta, Speis. 



4 (3) Legs for the most part not entirely 



yellow, often with a black pattern, 

 or at least with dark markings ; if 

 tlie legs are entirely yellow', the 

 abdominal spots are not so broad 

 and of triangular shape. 



5(12) Legs mainly yellow, that is, the front 

 femora not blackened at the base, 

 the trochanters yellow, the hind 

 femora and tibia3 only with black 

 rings ; antennae almost entirely 

 yellow. 



6 (7) Arista slightly pubescent; legs more 



or less darkened or wholly yellow, 

 without any definite black ring 

 before the apex of hind femora ; 

 abdomen of male very narrow ; 

 yellow abdominal spot-*" of female 

 triangular in shape, and longer than 

 half the segment scahtre, Fabr. 



7 (6) Arista bare; legs with sharply de- 



fined black rings on bind femora 

 and tibiae ; abdomen of the male 

 broader (annulipes, s. 1.). 



8 (11) Second abdominal segment with a 



pair of yellow spots. 



9 (10) Yellow spots on the second abdominal 



segment rectangular in shape and 

 not different from those on tho 

 following two segment?, which are 

 besides longer than the half of each 

 segment; hind tibiae with a sharply 

 defined black ring; hind tarsi yel- 

 low, darkened apically anmthpes, Macq. 



10 (9) Yellow spots on the second abdominal 



segment rounded, and only half as 

 large as the other?, which besides 

 are not longer than the half of the 

 segment ; hind tibiae and hind tarsi 

 sometimes entirely biack var. automenes, Walk. 



11 (8) Second abdominal segment wholly 



c2 



