49 



running about on old trees searching the holes made by other insects. When captured, 

 many of the species will roll themselves into little balls, by folding the head upon the 

 breast and bending the abdomen under so as to cover it. The abdomen consists apparent- 

 ly of three, four, or (in the male of Oleptes) of five segments, thus differing from that of 

 bees and wasps. The missing segments are diminished in size and are retracted within 

 the others so as to form a telescopic sheath for the ovipositor. The Chrysids are parasitic 

 in their mode of life, chiefly upon bees and wasps, laying their eggs in the nests of various 

 genera. The grubs of some species are known to feed upon the larvae of their hosts, while 

 others content themselves with devouring the store of nourishment laid by for these, and 

 starving the rightful inhabitants of the cells. 



The next five families, Mutillidae, Scoliadae, Sapygidae, Pompilidse, and Sphegidae, have 

 been grouped under the title of Fossorial Hymenoptera, because the habit of digging or bur- 

 rowing is characteristic of the greater number. 



Mutillid^;. 



These are ant-like insects, known generally as " Solitary Ants." The females have 

 no wings, but the males are usually furnished with them. Both species and individuals 

 are rare in Canada ; only two species are recorded, and a single female of Methoca bicolor 

 is the only capture I have made here. Although having much the appearance of ants, 

 they may be recognized by the absence of the knot, or scale, which is found in ants 

 between the thorax and the abdomen. 



SCOLIAD^E and Sapygidjs. 



Of these families we have also but few representatives ; about half-a-dozen species. 

 They are solitary in their habits ; the females of some species making deep burrows in the 

 earth in which to deposit their eggs, and a supply of food for the larvae therefrom. Other 

 species are said to be parasitic on the grubs of beetles, etc., and a few to be inquilinous 

 (self invited guests) in the nests of certain wild bees. Our commonest and largest species 

 is Tiphia inornata, which is thought by Provencher to feed in the larval stage upon the 

 grubs of Lachnosterna fusca. 



PoMPILIDiE. 



This family is more rich in species, for thirty are recorded, and undoubtedly many 

 remain to be discovered, especially in the west. Nearly all these are black insects, 

 sometimes with a bluish tint, or with markings of red, white, or yellow. They are of 

 slender form, with the wings generally clouded, and sometimes very black. The legs are 

 long and frequently spinous, and enable the insects to burrow in the sand with great rap- 

 idity ; whence they have derived the name of " sand- wasps." 



Our species are included in four genera, of which Pompilus contains more than half 

 the species. These have the legs furnished with spiny hairs, and construct with ease deep 

 burrows in sand or loose soil, in which they store caterpillars, etc. The sting which 

 they carry, and are quick to employ, is a formidable weapon, but the wound inflicted is 



not nearly so severe as that of the true wasp. 

 Pompilus aethiops is our largest species, measur- 

 ing sometimes three-quarters of an inch in length, 

 and is of a rich deep black colour ; the wings 

 black, with a purplish tinge. P. biguttatus is 

 a more common insect ; black, with white 

 marks on the abdomen, and sometimes on other 

 parts of the body. 



The genus Priocnemis, instead of having 

 the posterior tibiae with spinous hairs, has the 

 outer edge of them toothed, or serrate. In 

 other respects the species are almost undia- 

 tinguishable from Pompilus. In Agenia (Fig. 

 36, nest a) and Oeropales the legs are unarmed, and, especially in the latter, very long 

 and slender. 



4 EN. 



Fig. 36, nest a. 



