10 E. T. CRESSON. 



First segment small, quadrate, scarcely dilated at apex; head transversely 

 suhquadrate when viewed from ahove, broader than thorax, which is 

 long, narrow, suboompressed laterally 34. 



34. Metathorax above with a median silvery pubescent stripe ; head above with a 



transversely triangular silvery spot; second segment of abd(mien with 

 two small spots on basal middle, and a band on apical margin, inter- 

 rupted on middle, silvery pubescent 39. calvaria Cress. 



Metathorax with a silvery stripe on each side ; face and vertex ochraceous; 

 second segment of abdomen with a broad band at apex, interrupted on 

 middle, and two rows of spots on segments 3-5. silvery pubescent. 



40. felix Cress. 



Metathorax entirely silvery, except a black stripe on disk ; head entirely 

 black ; two large round spots on base of second abdominal segment, 

 and two square spots on apex of segments 2-5, dull golden or cupreous 

 pubescent 41. crusa Cress. 



35. Second segment of abdomen with two round or ovate yellow or red spots- -36. 

 Second segment with four spots, those at ba.se generally smaller and elongate, 



sometimes reduced to mere dots or obsolete 53. 



36. Head large, suhquadrate, broader than thorax 37. 



Head of usual size, not broader than thorax 43. 



37. Front of head projecting over the face like an overshoot, the lateral angles of 



projection prominently toothed ; the two ovate reddish spots on second 



segment opaque 42. project! Irons Cress. 



Front of head not projecting, unarmed 38. 



38. First segment of abdomen broadly dilated at apex, and conforming in out- 



line with base of second segment 39. 



First segment not conforming in outline with base of second, but more or less 

 constricted at apex, or small and suhquadrate 42. 



39. Pubescence above short and generally velvety black 40. 



Pubescence above long and entirely brownish ochraceous, depressed, almost 



biding the silvery stripes on each side of head and thorax, as well as 

 the two small, rounded, shining, yellow spots on second abdominal 

 segment 46. bonibycina Cress. 



40. Segments of abdomen beyond the second with a median stripe of silvery 



pubescence 41. 



Segments beyond the second with the sides silvery and the middle black; 

 stripe behind each eye, and on sides of thorax above not reaching 

 anterior margin, silvery pubescent ; the two rounded, yellowish spots on 

 second segment punctured ; thorax slightly longer than broad. 



44. turiialiN Cress. 



41. Spots on second segment of abdomen small, round, yellowish ; silvery pubes- 



cent stripes on thorax entire 43. araxa Cress. 



Spots on second segment large, longitudinally ovate, and covered with dense 

 appressed liright cupreous pubescence; the silvery stripes on thorax 

 abbreviated anteriorly ; size small 45. ciiriosa Cress. 



42. First segment of abdomen broad and constricted, but not toothed, at apex ; 



head unusually large, depressed, and when viewed from above subtri- 

 angular, being broader in front, very long behind eyes, with posterior 

 angles acute ; stripe behind eyes and on each side of thorax, spot on 

 disk of first segment and stripe on middle of apical segments, silvery 



