680 EXTERNAL ANATOMY OF INSECTS. 
flat and obtuse; in Qénas it is obconical, concave at the 
extremity, and apparently furnished with a sucker; in 
Ateuchus smaragdulus the anterior, and in Copris Carolina 
the posterior is forked and emarginate; in Sirex the 
former is hooked and winged ; in Lamprima it is triangu- 
lar and dilated; in Aphodius analis it is dolabriform ; in 
Dynastes retusus and Juvencus the spurs are bent like a 
bow. In many Hymenoptera, as the Sphecida, they are 
pectinated *, with a series of minute parallel spines—a 
structure which assists the animal in burrowing®; in 
Acanthopus they are armed with little teeth or spines ¢; 
in the hive-bee the spur of the cubit is furnished with a 
membranous appendage which I have called the velum ¢ ; 
and in a subgenus related to Saropoda (Ctenoplectra 
K. MS.), the interior spur of the posterior leg is cres- 
cent-shaped, fixed transversely, and fitted on the inner 
side with a membrane, the edge of which under a power- 
ful magnifier appears finely pectinated. 
e. Tarsus or Manus‘. This is the last portion of the 
leg, usually supposed to be analogous to the hand or 
foot of vertebrate animals; but, according to the hypo- 
thesis so often alluded to, rather the representative of 
their jointed finger or toe. In treating of this part I 
shall consider its articulation with the tibia, and of its 
joints znter se ; the number of those joints; their propor- 
tion and shape ; their parts and appendages. 
I seem to have observed three kinds of tarsal articula- 
tion. The first is a species of enarthrosis or ball and 
* Prats XXVIL Fire. 33.0". 
> Tann. Trans. iv. 200, Note a. * Pirate XXVII. Fic. 32. vo”. 
* Ibid. Fic. 36. a’. 
¢ Prates XIV. XVOXXVI, XEXVIT. 2’, 2’. 
