120 MODERN CLASSIFICATION OF INSECTS. 
The genus Xiphydria Latr. ( fig. 72. 4. X. Dromedarius ? ) has 
been the subject of much confusion as regards its relations. Linnaeus 
united it with Sirex ; and Klug introduced it, with Cephus and Orys- 
sus, into his Monographia Siricum. Latreille, however, always placed 
it, with Lyda and Cephus, as a distinct terminal section of the Tenthre- 
dinide ; remarking, however, “ Xiphydrize Cephique corporis forma, 
oviductu exserto, elongata, cum Tenthredinetis et Uroceratis ambi- 
gentes, ad familiam secundariam accedere videntur” (Gen. Cr. Se. 
vol. ili. p. 238.), which evidently induced Leach, followed by Stephens, 
to form Xiphydria, Cephus*, and Xyela into a separate but inaccurately 
characterised family, Xiphydriade. The discovery of its preparatory 
states enables me to prove its connection with Urocerus ; although, 
like Cephus and Xyela, it serves, in its perfect state, to form the pas- 
sage between the two families Tenthredinide and Uroceride. The 
mandibles are small, like those of Urocerus; but the lower parts of 
the mouth differ from that genus, as well as from any of the saw-flies. 
The maxille ( fig. 72. 5.) are elongated, and terminated by two mem- 
branous Jobes ; the maxillary palpi are 5- (not 4-) jointed; the basal 
joint being minute but distinct, the second very long and slender, and 
the three terminal joints short. Compared with the maxillary palpi 
of the Tenthredinide, these organs are small and weak. The labium 
( fig. 72. 6.) is elongated and membranous; and it appears to me to 
be entire, although Hartig figures it as deeply trifid (pl. 8. fig. 11.), as 
in the Tenthredinide. (Dr. Klug also describes it as “ vix emargina- 
tum, vel potius integrum,” Jon. Sir., p.12.) The labial palpi are 
much stronger than the maxillary, — thus proving the relation of this 
genus with Urocerus, — and 3-jointed. In one of the labial palpi which 
I examined in X. Dromedarius, the basal part of the terminal joint was 
constricted, and which has evidently led Hartig to figure it as 4-jointed 
(tab. 8. fig. 12.). The prothorax is greatly elongated, and very low, 
and the collar elevated, which has induced the specific names Ca- 
melus and Dromedarius. The peculiar structure of the calcaria of the 
fore legs and of the tarsi has been overlooked by all writers. The an- 
terior tibiz are terminated by a single broad curved spur (which is 
the peculiar character of Urocerus); although all the tibiae are stated 
to be terminated by two spines, by Klug, Stephens, &c. (which is the 
* In his Illustrations, Mr. Stephens has united Cephus with the Tenthredinide, 
leaving Xiphydria and Xyela alone in the family of Xiphydriade. 
