49 o Saw-flies, Gall-flies, Ichneumons, 



WASPS. 



We have now to take up the more familiar groups of wasps, bees, and 

 ants, in all of which the females (and the sterile workers in those species in 

 which such kind or caste of individuals exists) have a sting. The sting 

 (see description of that of the honey-bee on p. 460) is really the same struc- 

 ture as the slender, pointed, often long ovipositor of the parasitic Hymen- 

 optera; but whereas in the saw-flies, horntails, and true Parasita this instru- 

 ment is used for piercing or drilling a hole and placing the egg in it or on 

 the body of the host the egg passing along the whole length of the ovipositor 

 and issuing from its tip in. the so-called aculeate Hymenoptera, that is, the 

 stingers, the egg issues from the body at the base of the instrument which is 

 itself used as a weapon of offence and defence. In most of the ants of our 

 country the sting is rudimentary and functionless, but traces of it and its 

 poison can be found. 



The Hymenopterous insects referred to by the generic term wasps are 

 many and various, and their multiplicity and variety have led to the formula- 

 tion of many contradictory schemes of classification for them. That adopted 

 by Comstock in his Manual groups them in two superf amilies : one, the Sphe- 

 cina, or digger-wasps, including fourteen families; the other, the Vespina, or 

 so-called true wasps, including but three. The Vespina include the social 

 forms, as the yellow-jackets and the hornets, composing the family Vespidae, 

 one family of solitary parasitic wasps, the Masaridae, and one other family of 

 solitary mason, carpenter, leaf-cutting, mining, and digging wasps, the 

 Eumenidae. The Sphecina include wasps all solitary (not social), but some 

 of them parasitic, some inquiline, some earth-diggers, and some carpenters 

 and wood miners. The structural character separating these two super- 

 families is the longitudinal folding or plaiting of the wings in the Vespina, 

 a condition not present in the Sphecina. Some systematists refuse to recog- 

 nize so many distinct families while others would perhaps subdivide them 

 into a still larger number. The latest classification, that of Ashmead, recog- 

 nizes two superfamilies, the Sphecoidea, or insect-catching wasps, including 

 twelve families whose species are all solitary, none parasitic, and all diggers 

 or miners, and the Vespoidea, including sixteen families of social, parasitic, 

 guest, and mason wasps, together with a few diggers. The structural char- 

 acter separating these two great groups of wasps is the extension of the pro- 

 notum back to the tegulae or shoulder-tippets (or the absence of the latter) in 

 the Vespoidea, and the failure of the pronotum to extend back as far as the 

 tegulae in the Sphecoidea. All the bees agree with the Sphecoidea in this 

 character, so that Ashmead thinks the Sphecoidea more nearly related to 

 the Apoidea or bees than the Vespoidea are, despite the fact that all the 



