540 HYMENOPTEKA. 



Urocerus nitidus} the polished horn-tail, is an unde- 

 scribed species, for which I am indebted to the Rev. L. 

 W. Leonard. The male is not known to me. The female 

 is of a deep blue color, downy on the head and thorax, 

 smooth and highly polished on the abdomen, the end of 

 which is armed with a flattened horny point. Her wings 

 are clear and perfectly transparent, with brownish veins, 

 and have only a faint smoky tinge towards the tip. Her 

 legs are ochre-yellow. The body of this insect measures 

 rather more than three quarters of an inch, exclusive of 

 the horn on the tail. This insect differs from the European 

 Urocerus Juvencus in the much greater brilliancy of its color, 

 and in having shorter antennas. The borer of this and of 

 the preceding species resembles, in form and structure, that 

 of the pigeon Tremex, and is used in the same way. 



Urocerus abdominalis* the black and orange horn-tail, 

 of which only the male is known to me, has not been 

 described before. It is black, with the four middle seg- 

 ments of the abdomen deep orange. There is a pale yel- 

 low spot behind each eye ; the front corners of the thorax 

 are pale brownish-yellow ; and there are two minute yel- 

 lowish scales on the back part of the thorax. The abdo- 

 men is flattened and widened behind, and ends with a 

 flattened or triangular point. The antennae are long and 

 tapering, of a reddish brown color, with the two extremi- 

 ties black. The wings are transparent, with brown veins, 

 and are a little smoky at the tips. The first four legs are 

 ochre-yellow, with black thighs ; and the hind legs are 

 black, with yellow knees and feet. This insect varies in 

 length from six tenths to more than three quarters of an inch. 

 It is found in July, on the trunks of the white pine. 



Mr. Westwood has ascertained that the grubs of the 



[ ! Urocerus nitidus. This is the cyaneus of Fab. Syst. Piez. p. 50. — Norton.] 



* So named from the great contrast in the colors of the abdomen. In my 

 "Catalogue" it stands under the genus Sirex of Linnaeus, which is the same as 

 Urocerus of Geoffroy. 



