WALSH — DESCRIPTIONS OF N. AM. HYMENOPTERA. 65 



Descriptions of North American Hymenoptera. 



By Benj. D. Walsh, M.A. 

 (with notes by e. t. cresson.) 



[Among the MSS. left by my deceased friend, Mr. Benjamin D. Walsh, 

 was found that from which is prepared the present memoir, containing de- 

 tailed and carefully written descriptions of many species and a few new 

 genera of North American Hy?ncnop(era. 



Before the MS. (referred to me by Mr. C. V. Riley) came into my hands, 

 I had published in the Trans. Am. Ent. Soc, Sept., 1870, a paper on the 

 Sub-family Pimplarice, in which many species described by Mr. Walsh (in 

 the MS.) as new, were published under other names. In order, therefore, 

 to prevent an unnecessary increase in the synonymy of species, the names 

 given them by Mr. Walsh were suppressed as of no value, and those having 

 priority substituted. The descriptions are carefully prepared, and the com- 

 parative remarks, for which Mr. Walsh was always famous, exceedingly 

 valuable to the student. 



I owe much to the kindness of Dr. Wm. LeBaron, State Entomologist 

 of Illinois, who made the identification of the species quite an easy task, by 

 placing in my hands for comparison the specimens from which Mr. Walsh 

 made his descriptions. These, together with about three-fourths of the cele- 

 brated Walsh Collection, were, most unfortunately, destroyed by the terri- 

 ble conflagration that visited the city of Chicago in October, 1S71. 



I have only to add that all that is given below is from the original MS. 

 of Mr. Walsh, excepting the few notes enclosed within brackets.] 



Family TENTHREDOID^. 



Genus HYLOTOMA. 

 HjlotOllia SCUtellata, Say, $ . — Bright sanguineous. Head blue- 

 black, highly polished and glabrous. Clypeus finely but distinctly 

 rugose, emarginate in an angle of about 135 , the apex of which is 

 sometimes more or less rounded off so that the emargination approxi- 

 mates more or less to a circular arc of about 60°. Labrum transverse, 

 squarely truncate at tip or slightly emarginate. Antennae f as long as the 

 body, black, very rarely (1 $) tipped with rufous; the long terminal joint 

 finely rugose and opaque, but unarmed. Thorax highly polished and gla- 

 brous ; a vertical stria, having the appearance of a suture, always dividing 

 the side of the collare into two subequal triangles in the dried specimen. 

 Prothorax, tegulae, mesonotum except almost always the scutel (iS out of 

 21 $), anterior angles of the collare or very rarely (1 $) only its extreme 

 anterior angles, lower surface of the mesothorax up to the suture dividing 

 it from the sanguineous pleura, and the entire mesothorax, including the 

 basal plates, all blue-black. Very rarely (1 $) there is a lateral sanguine- 

 ous spot on the basal plate. Cenchri whitish. Abdomen polished and gla- 

 brous ; basal membrane pale luteous. Last ventral joint more or less tinged 

 iii— r [May 7, 1S73.] 



