192 ORDER HYMENOPTERA. 



The sexes differ considerably both in markings and size. The borer of the female consists 

 of five pieces : the two outside pieces are grooved for the reception and support of the 

 inner pieces, forming a hollow tube when closed together ; the inner pieces are needles, 

 with which the trunks of trees are pierced for the purpose of depositing the eggs. Their 

 young are grub-like larvse which are wood-eaters, and destroy forest trees by extensive 

 burrowing in the green solid matter. Pines, elms, maples, buttonwood and fruit trees are 

 all subject to attacks of the uroceridsB. 



Urockrus albicornis ( Fabricius). ( Plate xxxii, fig. 3.) 



Female : Color deep blue-black : stemmata three, situated behind the antennae in a 



triangular form ; head confluently punctured ; antennee rather long, white, the base 



and extremity dark brown or black. Behind the eyes there are two oval cream-colored 



spots. Thorax pubescent, punctured, and deeply impressed with a fissure running in a 



circular manner from the base of one forewing to the other, and also extending down 



the base of the wings, leaving an elevation with its point directed backwards. 



Abdomen cylindrical, smooth, shining, marked by a lateral oval white spot, and 



terminated by a lanceform appendage. Legs black, with white joints. Length one 



inch : ovipositor, nearly three-fourths of an inch; expanse of wing, nearly 2 inches. 



This insect resembles the female sirex, but may be distinguished at once by its white 



markings. 



Tremex coLOTriBA. (Plate xxxii, figs. 1, 2.) 



Tremex ( Jurine). Sirex ( Linnaeus, Drury). S. cinctus { Drury). S. pennstlvanicus (Degeer). 



Pigeon Tremex ( Harris). 

 Head and thorax yellowish brown, thick : antennae of the length of the thorax, and made 

 up of sixteen joints : abdomen bluish black, cylindric, ornamented by six rings, the 

 last interrupted at the median line of the body ; extremity yellow : ovipositor short 

 and stout : wings opake brown and clouded : legs and feet yellowish ; tibia armed 

 with a spur. 

 This insect is common in Albany county. In company with the Pimpla lunator, multi- 

 tudes resorted to a half-grown maple tree in the back yard of the Old State Hall for the 

 purpose of depositing their eggs. So completely was this tree riddled with holes when the 

 insects escaped after transformation, that it died in a few years, when it was found to be 

 perfectly mined through and through. 



I have taken this species also in Maryland, so that it appears to be widely distributed. 

 The ovipositor is nearly half an inch in length ; the body, an inch and a half; the male 

 less, but it frequently happens that the female is small also : expansion of wings, two and 

 a quarter inches. Their wants are not confined to the maple tree : they bore or pierce the 

 elm and buttonwood, which are thus killed in process of time. When a tree is resorted to 

 for the deposition of their eggs, it furnishes the larvae during every season of the year. 



