FOOT ON SOME NATIVE HYMENOPTERA. 81 



mons, the gall-making insects, and the Chrysididae (ruby-tails). 

 Among the Terebrant Hymenoptera exhibited there is a variety of the 

 female of Tenthredo umbigua, taken at rest on the blossom of a Scotch 

 thistle ; several very fresh specimens of Tenthredo viridis, of both 

 sexes, found running over the leaves of young and rank plants of 

 Urtica dioica ; and a female of Dolerus coracinus found kicking on its 

 back in the sand near Malahide. 



The tibiae of the fore-legs of the Sawflies have two spurs, by which 

 character either sex of the Sawflies can be distinguished from the 

 "Woodborers without the trouble of dissection. 



There are a few of the Entomophagous sub-section of the Terebrant 

 Hymenoptera in the boxes in the specimens of the Gn. Chrysis, known 

 as ruby-tails or fireflies. These insects, when taken hold of, make an 

 aggressive use of their ovipositor, which, though it cannot be considered 

 as a sting, more than the prickle of a furze bush can, because there is 

 no poison bag attached, may yet pierce and hurt the soft skins of 

 children: hence these beautiful insects are generally treated with great 

 respect when found on the panes of the windows in a nursery in the 

 hottest days of July. These insects are parasitic, depositing their eggs 

 in the cells of sandwasps and wild bees. "When attacked they roll 

 themselves up by turning the abdomen underneath the thorax in an 

 extreme degree of emprosthotonos, and, being sting-proof, the only way 

 the owner of the invaded nest can injure them is by cutting off their 

 wings, which mutilation, however, does not prevent them from accom- 

 plishing their object of depositing their eggs in a ready-made nest. 



The Ichneumonidee form a very large family of the Terebrant 

 Hymenoptera, containing about 120 genera, and more than 1100 

 species. There are in this box only eight genera and twenty- three 

 species. Ichneumons are easily recognised by their pinched waists. 

 The long and slender abdomen is set on to the body of the insect by a 

 small point, or by a fine stalk at the extreme end of the thorax, between 

 the hind legs. The ovipositor, which is a needle-like organ, consisting 

 of a horny sheath, guarded by a pair of valves, and enclosing two 

 slender serrated bristles, is in some specimens short, and concealed 

 within the abdomen ; in others visible, and occasionally of great 

 length, considerably exceeding that of the body. The Ichneumons 

 and the Gallflies are comprised in a division of Terebrant Hymenop- 

 tera called Spiculifera, or. dart-bearers, from the elongated character of 

 the ovipositor. The use of the Ichneumon family in nature appears to 

 be to check the destruction of vegetation by the larvse of other insects. 



Of the large cuckoo bees there are two males and two females of 

 Apathus rupestris, parasitic on Bombus lapidarius, and a female of 

 Apathus campestris, parasitic on Bombus subterraneus. The resem- 

 blance between these parasitic bees and their hosts is very close, and 

 there appears to be great harmony between the idle and the working 

 bees. There are but two sexes in Apathus. 



Of Bombus there are here six species. Eighteen are given in Mr. 

 Smith's Catalogue of British Hymenoptera. The derivation of the 



