UROCEUID.E.— SIllEX. 113 



Gf.nus XXXIV.— SIREX, Liniic. 



Anterince &\form or setaceous, as long or longer than the thorax, articulations 

 varying from 17 to 26, generally most in the female ; the 1st and 3rd joints 

 longest, of equal length, the former robust, 2nd minute globose, 4th shorter 

 than the 3rd, the remainder very gradually diminishing in length : paljri 

 unequal, very short, maxillary ciliated and 2- or 1 -jointed; labial thrice as 

 long and more slender, very pilose, with 4, 3, or 2 joints, the termhial one 

 robust: mandibles thick, 3-dentate : head moderate, semiglobose : et/es 

 small : ocelli 3 : thorax rather wider than the head, the anterior angle or 

 collar produced : loings with 2 marginal and 2 submarginal areolets : 

 abdomen long, cylindric, terminating m an elongate point, and in the female 

 with an elongate ovipositor arising from beneath the 6th segment, and 

 extending considerably beyond the apex of the abdominal appendage : legs 

 moderate ; posterior pair slender in the females, in the males with their tibife 

 and tarsi much dilated. Larva soft, cylindric, with six legs, the terminal 

 segment rounded, and plicate, armed with a short spine : pupa folliculated. 

 As before alluded to, the insects of this conspicuous genus differ 

 considerably in parts (the trophi) that are usually considered as 

 being of great moment in the determination of genera, but there 

 appear so many preponderating external characters of similarity as 

 not to warrant the separation of the discordant species ; I shall there- 

 fore merely indicate their discrepancies from Klug. The larvas feed 

 on the inner substance of fir trees, boring large cylindrical holes, and 

 committing sad havoc where they abound. 



A. Maxillary palpi biarticulate ; labial 4-articulate. 



Sp. 1. gigas. Capite nigro, macula pone oculos utrinque Jlava, abdomine {^in 

 fosmina) Jlavo, segmentis 9,-do, 7-mo, 8-vo nigris, 1-mo et 9-no basifuscescen- 

 tibus. (Long. corp. $ 1 unc. 3 lin. ; ? ovip. inch 9 lin. — 1 unc. 5§ lin. ; 

 Exp. Alar. ? 16 lin.— 2 unc. 2 lin.) 



Si. gigas. Linne. — Samouelle, pL S.f. 3 ?. — Steph. Catal. 342. Xo. 3997. 



Head pilose black, with an obscure luteous spot below the antennae, and a 

 large yellow lateral oval glabrous one on each side behind the eyes : 

 mandibles ferruginous at the base; ocelli yellow; eyes fuscous; thorax black; 

 abdomen a little silky above, the base of the 1st segment brownish, the 2nd 

 entirely yellow above, 7th and 8th the same, 9th yellow above and below, 

 excepting the base of the upper surface, which is brownish, its appendage 

 also yellow ; ovipositor ferruginous; femora black, 4 anterior yellow at the 

 tips; libige and tarsi entirely yellow; wings hyaline, yellowish, with the 

 nervures and costa ferruginous, stigma dusky-black ; antennte luteous. 



Male with the abdomen luteous, the 1st and last segment and its appendage 

 black ; the hinder pair of tibia and tarsi fuscous, pale at the base. 



Extremely variable in size. 



Mandibulata, Vol. VII., Sept. 30th, 1835. h 



