1899. J NATURAL SCIENCES OF PHILADELPHIA. 63 



SYNOPSIS OF THE UNITED STATES SPECIES OF THE HYMENOPTEROUS 



GENUS CENTRIS Fabr. WITH DESCRIPTION OF 



A NEW SPECIES FROM TRINIDAD. 



KY WILLIAM J. FOX. 



This genus of bees is of tropical origin and, north of Mexico, is 

 only found along the extreme southern border of the United States. 

 Of the eleven species herein noted ten are from the region bor- 

 dering the Rio Grande, and one only is found east of Texas, C. 

 errans, from the vicinity of Biscayne Bay, Florida, a species prob- 

 ably introduced from the West Indies. Ten of these eleven species 

 have been first described within the past two years. 



The author is indelited to Mi's. A. T. Slosson and Messrs. Cock- 

 erel], Ashraead and Griffith for the loan of material, which has 

 been of much assistance. 



FEMALES. 



1. Abdomen green-black, with reddish maculation, entirely red- 



dish testaceous beneath; (face Avith pale markings, an in- 

 verted T-shaped mark on clypeus; pubescence of thorax above 

 pale fulvous, on sides, beneath, and on head in front pale 

 gray ; a stripe of black hairs crossing the vertex), errans n. sp. 

 Abdomen deep black, more or less pubescent, 2 



2. Griseous pubescence covering the entire body, that on thorax 



above and vertex slightly fulvous, while the hair on legs 

 from middle of tibite to apex of two hind pairs and anterior 

 tarsi, black; abdomen pruinose; labrum in perfect specimens 

 densely pilose; a triangular yellow spot on clypeus; antennae 

 entirely black, the first joint of flagellum distinctly longer 

 than the united length of four following joints, pallida n. sp. 

 Abdomen, at most, with pale pubescence on first and second dor- 

 sal segment, generally quite nude, 3 



3. Only the first dorsal segment pubescent, 4 



" The second abdominal segment, as well as the first, delicately 



pruinose, ' ' 



Hoffmannseggice CkW. {^lanosa Ckll. 9 uon Cress.) 



