420 Introduction to Animal Morphology. 



(workers). Osmia makes thimble-like cells. Xylocopa, car- 

 penter-bees, cut passages in old wood. 2. Vespidae, Wasps — 

 often naked ; antennae slender, notched and bent ; eyes reni- 

 form ; prothorax elongated to the wing roots ; maxillae often 

 leathery; wings longitudinally folded. They are solitary, or co- 

 lonial, and the latter have workers, like those of bee colonies. 

 The nests are of paper-like vegetable pulp. Vespa and Po- 

 listes are the ordinary social wasps, whose colonies consist 

 often of workers, until the end of the season, when the males 

 and females appear. In the latter genus parthenogenesis oc- 

 curs. Polybia and Epipone chartaria build large conical nests 

 in S. America. Eumenes, Odynerus, and other solitary ge- 

 nera build clay nests. 3. Crabronidae — antennae short, not 

 bent ; mandibular palp, six, — labial, four-jointed ; forewings 

 not folded, narrow ; sting not barbed, nor broken on being 

 used. The female either kills prey to feed her larvae (Bem- 

 bex), and brings it to them daily, or paralyses other larvae by 

 injuring their nerve-cord, and brings them in numbers into 

 the nest, providing the young at once with enough food for 

 their whole larval state (Cerceris, Sphex, &c.) Tachytes is a 

 cuckoo wasp, like the nomade bees, laying eggs in the nests 

 of Sphex. 4. Pompilidae, Sand wasps — antennae long ; pro- 

 thorax stretching to the wing roots ; wings large, broad, the 

 fore with three cubital cells; legs spiny. 5. Heterogynae — 

 sexes dimorphic ; females wingless (Mutilla, &c.), or nearly 

 so (Sapyga, Myzine, &c.) ; mostly parasitic on other Hyme- 

 nopters. 6. Chrysididae — metallic coloured, with bent 13- 

 jointed antennae ; 3-4-ringed abdomen ; one cubital cell on 

 the forewing. 7. Formicidae, Ants — colonial ; males and fe- 

 males winged, but workers apterous, with small thorax, eyes, 

 and no ocelli ; an anal gland, secreting formic acid, which 

 acts as an irritant. Some feed on the sweet, honey-like sub- 

 stance which they suck from Aphides. Formica rufa, the 

 red ant, builds ant-hills ; Polyergus holds individuals of other 

 species as captives in its nest ; Myrmecocystis has a globular 

 abdomen ; Atta cephalotes is the visiting ant of S. Ame- 

 rica. 



Sub-order 2. Entomophaga — trochanter biannulate ; ab- 



