MOUTH. 243 



stinging Hymenoptera twelve in the females and thirteen in 

 the males; but in the Lepidoptera, Ichneumonidce, Ortho- 

 ptera, and many others, the number of the joints is much more 

 considerable, sometimes reaching fifty or sixty ; and in some 

 Orthoptera the number is still far more numerous. 



In a few insects the antenna? are very short and destitute 

 of joints, as in the Hippoboscidte, and in Dalman's genus 

 Articerus ; Bi-articulate (two-jointed) antennae are found in 

 Paussus, triarticulate antennae in many Diptera. The large 

 sawflies (Cimbices) vary in the number of their joints from 

 five to eight. 



It still remains to be noticed, that a very great diversity 

 often exists in the structure of the antennae in the opposite 

 sexes of the same species ; this is especially noticed in the 

 greatly increased length of these organs in the males, and in 

 the various hairs, feathers, or branches with which they are 

 adorned in this sex. Numerous other variations occur, such 

 as the incrassation of certain of the joints, or their greater 

 developement, to enumerate which would occupy too great a 

 space ; but in all which, these advantages are always in favour 

 of the male sex. 



(d) The Mouth* (M in the figures). 



If the structure of the antennae has required a considerable 

 portion of our attention, a still greater share must be now 

 devoted to the various and variable organs of which the mouth 

 of insects is composed, since it is upon these variations that 

 the most valuable arrangements of insects hitherto proposed 

 have, in a great measure, been established. If a beetle and a 

 butterfly, a house-fly, or an aphis be examined whilst feeding, 



* Obg. In the various figures representing the mouth of insects, the 

 same letter indicates the same organ throughout : n, is the upper lip, 

 labrum ; m, mandible ; nuc, maxilla ; mp, maxillary palpi ; c, chin or 

 mentum ; / 2, labium, or lower lip ; Ip, labial palpi ; t, tongue, lingua, or 

 paraglossae. 



