EXTERNAL ANATOMY OF INSECTS. 687 
C. sexguttata. ‘Though commonly the slenderest joint 
of all, particularly so in Raphidia, in many Heterome- 
rous and Lamellicorn beetles it is the largest, conspicu- 
ously so in Mellinus tricinctus. Sometimes as in Bupre- 
stis chrysis, &c., all the tarsal joints are nearly equal in 
length and thickness. 
We are next to say something upon the shape of the 
tarsi and their joints. In general we may first observe 
that their upper surface is commonly more or less con- 
vex, and the lower flat or concave: in insects that are 
swift runners, as the terrestrial Predaceous beetles, they 
are usually slender and filiform? ; in those that swim, as 
Dytiscus, the two posterior pair taper nearly to a point 
from the base to the apex®; in some that climb, as Bu- 
prestis, they are rather flat and linear; and in others (the 
Rhyncophora or Weevils) they grow gradually wider to- 
wards the claw-joint®; sometimes, as in Mordella, the 
four anterior ¢a7sz are of this shape, and the posterior 
pair setaceous. In Gyrinus the four posterior are flat 
and triangular; and in that extraordinary insect Gryllus 
monstrosus the tarsi are foliaceous and lobed*. In many 
males and some others the anterior pair or hands are of 
a different shape from the two posterior: thus in several 
Carabi they are lanceolate; in Staphylinus, Creophilus, 
&c. in both sexes they are often nearly circular, like 
those of male Dytisci*. With regard to the shape of 
individual joints it may be said in general that they are 
rather triangular, with an anterior sinus for the reception 
of the ‘succeeding joint: the first joint usually departs 
® Prare XIV. Fic. 7. ¢''. > Tbid. Fic. 6. t”. 
© Prats XXVEFE. Fic. 47. 4 Prate AXVII. Fie. 41. 
© Prate XV. Fie. 9. 
