AMERICAN HYMENOPTERA. 355 



ovate, the lower end pointed, the second and third each with a recurrent 

 nerviire; a broad lanceolate cell with oblique cross line; under wings 

 with two inner cells. 



Anfennse setaceous, as long or longer than thorax, from 17 — 25-join- 

 ted, first and third longest. 



Nf^ad moderate, semiglobose, generally narrower than thorax, eyes 

 somewhat kidney shaped ; labrum minute, elongate; maxilla; with two 

 lengthened setose lobes, palpi t-jointed; labrum produced, its palpi 

 3-jointed. 



The p)-ofho7-ox is produced into a short neck, the collar wide, ab- 

 ruptly elevated and angulate before. The metathorax is of two parts, 

 the hinder portion of which has been regarded by some as the basal 

 segment of abdomen. The ahdonirn long, wide, generally a little 

 thickened toward end, terminating in an elongate point or horn ; in 

 the female also with an ovipositor coming from beneath the sixtli 

 segment and extending beyond the apex of abdomen. The borer which 

 is inclosed between two horny sheaths, is hollow and nearly cyliudical, 

 with lateral grooves and with a separate piece in its lower side, com- 

 posed of smaller pieces so arranged as to assist the upper part both as 

 a support and n)i addition of power. This apparatus has sufficient 

 strength to enable the female to deposit the eggs at some depth in solid 

 timber. It is described and figured fully by Westwood, Hartig and 

 others. 



Westwood shows an analogy between the saws of the Tenthredinidae 

 and the borers of Urocerus, their general principle being alike, only 

 one is fitted for depositing eggs in tender leaves and stems and the 

 other in solid wood. 



The larvae are long, cylindical, fleshy grubs, six footed, the terminal 

 .segment furnished with a short spine. These larvae bore large holes 

 within the trees, often causing great destruction, especially in pine 

 forests. Mr. Westwood quotes the following statement: 



Mr. Raddon forwarded to the Entomological Society specimens of U. Juvencus. 

 accompanied by specimens of the wood of a fir tree from Beadley Forest, Wor- 

 cestershire, perforated by this insect. Of this tree, twenty feet were so inter- 

 sected by the burrows, that it was fit for nothing but firewood ; and being placed 

 in an out hoiise, the perfect insects came out every morning, five, six, or more 

 each day. The females averaged one in twelve for the first six weeks, but after- 

 wards became more plentiful and continued to make their appearance until the 

 end of November, females only being produced during the last two or three 

 weeks. (Trans. Ent. Soc. Vol. i, 85, App.) 



When full grown, the larvae are said to form a slender silken cocoon 

 mixed with chips at the end of their burrows. The pupa greatly re- 



