EXTERNAL ANATOMY OF INSECTS. 521 



few, arc always multiarliculate : — we will therefore, with- 

 out further delay, proceed to the Hymenoptera. In La- 

 treille's tribe Aculeata the general rule is, that the fe- 

 males shall have twelve joints and the males thirteen. 

 In his IcJmeamonides the law seems to be, that the an- 

 tennae shall be multiarticulate and setaceous; but in most 

 of the other tribes of the order, even those that in other 

 respects are most nearly related, — as in his Tenthredine- 

 tce, — the number of joints of these organs varies without 

 end. Thus in Hylotoma there are only three joints a ; 

 in Cimbex lceta h Jive; in C. axillaris and Perga Leach c , 

 six : and so on to twenty-five or more d . The same fluc- 

 tuation in this respect runs throughout , the rest of the 

 order. In the Diptera there are two general types of 

 antennas : — those of the Tipularia Latr., consisting usu- 

 ally of from fourteen to sixteen joints, in the males often 

 resembling beautiful plumes ; and those of the remainder 

 of the order, in which they do not exceed three joints e : 

 though the last, or patella, is often further divided into 

 obsolete or indistinct ones f . These antennas may be 

 farther subdivided into Jilatce and aristatce, or those 

 without and those with a bristle, either lateral or ter- 

 minal. 



The clothing of antennas 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 aud setaceous antennas of Predaceous beetles 

 (Cicindela L., Carabus L.) have the first two, three, or 



" Jurine Hymenopt. t. vi.f. 3. b Ibid.f. 2. 



-• Ibid.f. 1 . Plate XXV. Fig. 7- d Plate XXV. Fig. 25, 26. 



« Plate XII. Fig. 16—22. ' lbkl Fig. 19. a. 



