GENERAL CHARACTERS. 3 



palpi with from 1-4 joiiit.-^, and occasionally with slender filaments 

 or paragloss^, which vary in Icn^^th according to the size of the 

 maxillae. 



The Antenn.e (fig. 2) vary greatly in structure in the various 

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

 than in the females, and often curiously formed ; they are inserted 

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

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



groups having one-jointed trochantei*s. these 

 organs are usually filiform and simple, and 

 "^ almost uniformly composed of 13 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- 



niliform, clavate, fusiform, furcate, pectinate 

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

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

 oblong-ovate, rarely strongly dilated and shield-like, i\\e flngeUam (b) 

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

 separated by a ring-joint or pedicel, which in the Chalcidida3 and 

 Proctotrupida) is often composed of two or three minute joints. 



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

 oval, agglutinate mass, sometimes elongate and subcompresscd, higher 

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

 forms of Mutillidaj 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 prothontx (a), to which the anterior legs 

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

 above is usually termed the collar ; the j)osterior margin is often 

 arched, occasi(mally angular and sometimes extending back to tlie 

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

 upper porti(m of the thorax ; it is sometimes elongated into a neck 

 as in some of the Uroceridaj, Stephanidae, etc., while in certain genera 

 of the PompilidiTC it is almost quailrate and as large or larger than 

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

 extensively developed than citluT tlic protlidrax or metathorax. and 

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



