FOSSORES — FAMILIES. 105 



FOSSORES. 



This series, which c()ni])rises the ditterent families of sand and 

 wood wasps, is distinguished from the preceding by the form of tlie 

 abdomen, tlie petiole being simple, i. e. not formed into scales or 

 nodes, and the sexes consisting of males and females oidy. The 

 wings are never folded and are present in both sexes, exce2:)t in the 

 females of the Mutillidte which are always apterous. The legs of 

 the females are formed for burrowing, and not fitted for collecting 

 pollen, the basal joint of the posterior tarsi being subcylindrical, and 

 not dilated, flattened and densely hairy as in most of the Bees. 



The families composing this large series may be separated in the 

 following manner : 



Table of Families. 



Prutlionix considerahly iiroduced posteriorly, tlu' hiiuli'r atiales reaching the 

 tegulie ; 9 sometimes apterous, in wliich case the segments of the 



thorax are almost always soldered together 2. 



Prothorax usually consisting of little more than a narrow collar, the posterior 

 angles often lobately produced, but never reaching the tegula" : 9 



never ajjterous 3. 



2.— Abdomen with the first ventral segment distinctly separated from the second 

 by a more or less deep constriction or furrow. 

 Intermediate tibife with two apical spurs,* their coxse contiguous or nearly 



so; 9 apterous MUTILLID-^. 



Intermediate tibise with but one ai)ical spur (except in Myzine 9 ). their 

 coxae- widely sepai-ated (less so in Tix>hia %, and Myzine % ) \ 9 



always winged SCOLIIDJE3. 



Abdomen with the first ventral segment not separated from the second by 

 a furrow or constriction of the joint. 

 Posterior legs short, not reaching to the apt^x of the abdomen : eyes 



emarginate within SAPYGID^. 



Posterior legs long, reaching beyond the apex of the abdomen; eyes 



not emarginate within POMPILiID.,3E. 



3. — Anterior wings with three complete submarginal cells 4. 



Anterior wings with two complete submarginal cells 5. 



Anterior wings with but one coni))lete and distinct submargiiuvl cell (in 

 Trypoxylon the .second submarginal and third discoidal cells are 

 indistinctly defined) CRABRONIDiE3. 



"•■• In the 9 of Myzine in the Scoliidie. the intermediate tibise have apparently 

 two apical spurs, but then the marginal cell is long and narrow, and distinctly 

 separated from tlie anterior margin of the wing, and the third submarginal cell 

 extends far beyond the apex of the marginal, which is never the ca.se in the 

 MutillidtB. In species with spinose legs it is difficult to distinguish the ai>ical 

 spurs from the si)ines, the former, however, are generally colored ditfercntly from 

 the latter. 



TRANS. .\MEK. KNT. SOC. (14) SII'I'I,. V>>| . 1S>T. 



