520 EXTERNAL ANATOMY OF INSECTS. 
Perga’, siz: and so on to twenty-five or more’. The 
same fluctuation in this respect runs throughout the 
rest of the order. In the Diptera there are two general 
types of antennze:—those of the Tipularie, consisting 
usually of from fourteen to sixteen joints, in the males 
often resembling beautiful plumes; and those of the re- 
mainder of the order, in which they do not exceed three 
joints: though the last, or. patella, is often further di- 
vided into obsolete or indistinct ones¢. These antennee 
may be further subdivided into filate and aristate, or 
those without and those with a bristle, either lateral or 
terminal. 
The clothing of antennz also merits attention, since it 
is often not a little remarkable. By clothing I under- 
stand the down or hairs of every kind with which they 
are either generally or partially covered. A great number 
of filiform and setaceous antennee of the terrestrial Pre- 
daceous beetles (Geodephagena) have the first two, three, 
or four joints naked, and the rest covered with a fine 
down: thus in Patrobus two only are naked, in Platynus 
three, and in Helobia four. In insects that have a knob 
at the end of these organs, whether lamellated or perfo- 
liate, this down is often confined to it, or to its interme- 
diate joints, and seems intermixed with nervous papille. 
These are particularly visible in the flabellate antennee 
of Rhipicera, Lampyris Latreillii *, Elater flabellicornis*, 
&e. covering both surfaces of the processes of the joints, 
@ Jurine Hymenopt.t. vi. f. 1. Pirate XXYV. Fie. 7. 
»b PLrare XXV. Fre. 25, 26. © Prate XII. Fic. 16—22. 
qd Ibid: ‘Bre sOia, 
8° Dinas Tras es TKI. fo, 40 PLATE ARV: Fic, 11: 
f Pearse AT. Fie a7. 
