HYMENOPTERA. — TENTHREDINIDE. 91 
antenna Hytoloma ¢, 71. 6. ant. of Croesus Septentrionalis, 71. 25. 
ant. Cephus), but generally short, the basal joint not greatly elon- 
gated. Those of the males are in some species pectinated, furcate, or 
flabellate ( fig. 71.3. antenna Schyzocerus, 6, 71. 4. ant. Lophyrus, 
$, 71.5. Lophyrus  ). The labrum is mostly transverse or quadrate, 
with the anterior angles rounded and pilose (fig. 69. 7.); the man- 
dibles, which are larger in the males than in the females, are elongated, 
horny, narrow, compressed, and dentated (fig. 69. 3, 4, 5.) ; the max- 
ill are elongated, membranous, and bilobed, with the maxillary palpi 
moderately long and 6-jointed (jig. 69. 5. 8.); the labium is small, 
arising from the membranous connection at the base of the maxille, 
and is trifid at its extremity, and the labial palpi 4-jointed (fig. 69. 
4,5.9.). My jigs. 69. 2—13. represent various details of Trichio- 
soma Lucorum, jigs. 2—9. exhibiting parts of the mouth; fig.69. 2. 
shows the front of the head, with the jaws closed, and the labrum 
folded over them ; fig. 3. shows the jaws partially opened, and the 
labrum shut close down upon the maxillz and labium, which are folded 
up and at rest in the oral cavity, as represented in fig. 4., in which 
the labrum is lifted up over the mandibles; fig. 6. shows the mode in 
which the maxille and labium fold up; in fig. 5. these parts are 
stretched out to their full extent, showing the basal parts or stipes 
of the maxilla to be as long as the terminal parts; jig. 7. exhibits 
the labrum ; fg. 8. the maxilla; and jig. 9. the labium separately. 
The thorax forms a large solid mass, generally broader than the 
head, (fig. 72. 1. pro- and meso-thorax of a Cimbex, the prothorax 
dotted). The meta-thorax often exhibits two minute white spots (Cen- 
chri, fig. 72. 2.and 3. x and jig. 73. 6. and 7. x) at the sides of the 
part ordinarily termed the postscutellum. The hinder portion of the 

Bose. Sur une Nouv. Esp. Tenthredo (T. Boleti), Nouv. Bul. Soc. Phil. 1818, 
and in Journal de Physique, Nos. 86 and 87. — Ditto, on Cephus pygmzeus, 
in Bull. Soe. Nat. 1823. 
Villaret. Mémoires sur quatre Esp. Tenthred., Ann. Soc. Ent. France, tom. i. 
Brebisson, in Nouy. Bull. Soc. Philom. 1818 (gen. Pinicola. Xyela). 
Dalman, in Analecta Entomol. (Xyela). 
Schiffer. Die Tannensagflieger (Lophyrus Pini) in Abhandl. von Ins. 4to. 
Brullé, Metamorph. Cladius difformis, Ann. Soe. Ent. France, vol. i. 
Peck. Natural History of the Slug Worm, in the Collection of the Massach. Hist. 
Soc. vol. v. Boston, 1799. — (Ditto, published separately by Young and 
Minns). 
Linneus, Fabricius, Rossi, Panzer, Stephens, &e. 
