ORDER HYMENOPTERA. 



165 



the brightest, and in Bombus and Apatlms they are much 

 more variable in color than the females; in several species 

 of Xylocopa, while the females are black, the males are 

 bright yellow. (Descent of Man, i. 354.) 



The group Terebrantia includes those families in which 

 the ovipositor is normal, being adapted for boring, or so 

 modified as to form a saw-like apparatus; while the Aculeata, 

 including the ants, wasps, and bees, have a true sting.* 



Family Tenthredinidse. Abdomen sessile, not narrowed at the 

 base; ovipositor saw -like; anterior tibiae with two apical spurs; the 



FIG. 207. The larch saw-fly, natural size and enlarged, with the larch worm of 

 different ages, natural size. Miss L. Sullivan del. 



head is short and transversely oblong, with short, not elbowed, 

 usually simple, sometimes clavate or pectinate antennae. The larvae 



* In preparing the synopses of the characters of the families, the 

 author has often copied nearly vi'rfiittim from Cresson's " Synopsis of 

 the Hymenoptera of America, north of Mexico" (Phila., 1887). It 

 is not improbable that some of the " families" are merely sub-fami- 

 lies, as for example in the ants and wasps. 



