120 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.52. 



quently spot on mesopleurae, fasciae on tegites 1-6, first usually 

 roundly emarginate on anterior middle, second, and thii'd (some- 

 times fourth) biemarginate on anterior border, frequently lateral 

 spots on seventh, small lateral spots on second and third sternites, 

 distal part of femora variable in extent, tibiae except spot below on 

 fii'st pair and sometimes on second, tarsi except ultimate segments, 

 yellow. 



The color of the liiaculations varies from bright orange to pale 

 greenish yellow and the variation in the extent of their development 

 and in their combination on different inchviduals is such that the 

 description given above may not apply with absolute accuracy to 

 any single specimen. The clypeus is typically black, but it is fre- 

 quently bordered with yellow and it may be whoUy yellow. The 

 labrum likewise may be entirely black or entirely yeUow but it is 

 more frequently black with apical yellow • markings. The frons, 

 scape, and flageUum are black. Tlie variation in the maculations of 

 the thorax and abdomen are as great as on the head. The wings 

 may be heavily infumated in medial region or they may be hyaline 

 and in the series before me all degrees of infumation may be found. 

 The pubescence is short and white. On the frons and clypeus, 

 especially on well preserved specimens, it gives a bright silvery 

 reflection. It is shorter on the thorax and shows scarcely any sil- 

 veriness. Segments 6-8 of the flageUum bear evident pits on the 

 posterior surface ; the ultimate segment is rounded apically and only 

 very sHghtly curved. The second sternite bears a prominent, 

 smooth, median, longitudinal process that terminates posteriorly in 

 a short curved point. 



Female. — Black: Labrum wholly or in part, mandibles except 

 apices, usually apical border of clypeus, rarely scape below, narrow 

 posterior orbits, spot on tegulae, lateral lines on scutum, frequently 

 pair of discal marks on same, lateral spots on scutellum, fascia on 

 metanotum, curved fascia on dorsum of median segment, usually 

 spot on postero-lateral angles of same, spot on mesopleurae variable 

 in size, fasciae on tergites 1-5, fii-st roundly emarginate at midline 

 on anterior border, 2-5 biemarginate or bisinuate and usually with 

 median notch on anterior border, sixth tergite apicaUy or with apical 

 lateral spots, lateral spots on sternites 2-3, femora distally, tibiae 

 except line below, on first pair and sometimes on second, and tarsi 

 varying in degree, pale-yellowisli wUte or yellow. The wings are dis- 

 tinctly infumated on most specimens, but on some they are almost 

 hyahne. The pubescence on the clypeus and frons is short and 

 dense and gives a silvery reflection; on the vertex it is somewhat 

 longer; on the thorax and abdomen it is short and not conspicuously 

 silvery. 



Length. — 8-14 mm 



