GENERAL CHARACTERS. 3 



palpi with from 1-4 joints, ai;d occasionally with slender filaments 

 or paraglossae, which vary in length according to the size of the 

 maxillae. 



The Antenn.t- (fig. 2) vaiy greatly in structure in the various 

 groups, those of the males are generally longer and more developed 

 than in the females, and often '^uriously formed ; tiiey are inserted 

 (fig. 1, f ) usually on the middle of the face, sometimes nmch lower 

 down close to the clypeus, and rarely far apart. In most of the 



groups having one-jointed trochanters, these 

 organs are usually filiform and simple, and 

 D-, almost uniforndy composed of 16 joints in 



the males and 12 in the females ; while in 

 the ditrocha groups they vary greatly in 

 the number of joints, from 3 to 60, and 

 '^' "■ also in form, being setaceous, filiform, mo- 



' ^'^^^^ ' > se nilifi)rm, clavate, fusiform, furcate, pectinate 



and flabellate, rarely ciliate with long hairs ; they are sometimes 

 elbowed, the scape (a) simietimes very long, usually short, ovate or 

 oblong-ovate, rarely strongly dilated and shield-like, the flagellnm ( b) 

 being generally much longer than the scape, from which it is usually 

 separated by a ring-joint or pedicel, which in the Chalcidid* and 

 Proctotrupidte is often composed of two or three minute joints. 



The Thorax (fig. 3, upper portion) generally forms a compact, 

 oval, agglutinate ma.«s, sometimes elongate and subcompressed, higher 

 than wide, as a rule broader than high ; in some of the apterous 

 fornjs of Mutillidic the segments are soldered together, and in most 

 of the female and worker ants it is elongated and often more or less 

 strangulated and nodose, and sometimes spinose. It is composed of 

 many pieces, but for the purposes of this synopsis the divisions shown 

 in the cut will suffice. The prothorax (a), to which the anterior legs 

 are attached, is generally of small size and the portion visible from 

 above is usually termed the collar ; the posterior margin is often 

 arched, occjisionally angular and sometimes extending back to the 

 tegidce (f ) as represented in the figure, thus forming the front of the 

 upper portion of the thorax ; it is sometimes elongated into a neck 

 as in some of the Uroceritla;, Stephanida;, etc., while in certain genera 

 of the Pompilida; it is almost quadrate and as large or larger than 

 the raesothorax. The mesothorax (b) is usually larger and more 

 extensively developed than either the prothorax or metathorax, and 

 is either flattened or more or less convex, sometimes trilobed in fnmt. 



