MONOGRAPH OF THE NORTH AMERICAN PROCTOTRYPID^. 11 



dentate or pedicellate and vertieillate. In some groups the number of 

 joints is alike in both sexes, but in others they are more numerous in 

 the males, while in at least one group, the IJelytin.e, the females have 

 the greater number. 



The mandibles are in the majority of the groups bidentate or bifid, 

 but in th»' Bethylinai and Dryinina^ they vary from 2- to 0-dentate: 

 Apencsia has but 2; Epyris and Mesitius 5 or 0; i^derodenna 3 or A, 

 etc. Most of the genera in the Dryinina-i have 3 or 4; the ScelioninfB 

 2 or 3; while in only one gnmp, the Proctotrypina', are they eden- 

 tate. The maxillie, PI. i, Fig. 2, terminate in one or two large, thin, mem- 

 branous lobes, the galea and lacinia, while the mentum ia small, horny, 

 or coriaceous. The maxillary palpi vary in the number of joints from 

 2 to (i and ai i.sually conspicuous from beneath. The labial palpi, PI. 

 I, Fig. 3, on the contrary, are short ami inconspicuous, usually 2- or 3- 

 jointed, the terminal joint being the longest; while in one group, the 

 Platygasterina", they are 1-jointed. 



THK THORAX. 



The thorax is, as a rule, rarely very much narrower than the head, 

 variable in breadth and length in the different groups, and is of the 

 greatest importance in classification. Tlie three principal divisions are 

 the pro-, meso-, and meta thorax, an<l as it is essential that the compo- 

 nent parts of each of these divisions should be thoroughly understood, 

 they are here taken up separately, the i)arts being explained by letters 

 on PI. I, (Fig. 1, 7'.) 



The prothorax (Fig. pt) is large and conspicuous from above, with 

 but few excepti(ms, in the Bethylina^, Embolemina^, Dryinina^, Procto- 

 trypiufe, and in some of the Scelioninje, while in the other groups it is 

 more variable, usually short and inconspicuous, sometimes very small, 

 and often not^ or scarcely, visible from above {Telenommj etc.). It sup- 

 ports the lu'ad and front legs, and its principal component parts are: 

 (Fig. pu) the pronotum, (Fig. jt) tlie pleuron, and {Fig. s})) the praester- 

 num. 



The mesothorax is the largest division of the thorax. It supports 

 the front wings and the middle legs, ami variations and peculiarities 

 noticeable in its various sclerites have been found to be of excellent 

 specific and generic value. The princip.al sclerites are: (Fig. w«) me- 

 soscutum, w liich is frequently subdivided into three parts by longitu- 

 dinal furrows (Fig. j>/') called the parapsidal furrows; it is then said to 

 be trilobed. Fig. m becomes the middle lobe. Fig. p the parapsides 

 scapuhe or lateral lobes. Fig. s is the meso-scutellum, usually desig- 

 nated as the scutellum, and has usually at the lateral basal angles (Fig. 

 nx) two subtriangular sclerites termed axilhe. Fig. mps is the meso- 

 postscutellum, often visible only as a transverse band, carina, or fold, 

 and again quite distinct and armed with one or more strong spines or 



