72 The Ottawa Naturalist. [July 



crevices, some forming cells in the hollow, or excavated stems 

 of plants in which only the partitions are of mud, and others 

 making their nests in burrows in the ground. Like Eumenes 

 they provision their cells with caterpillars, but much yet remains 

 to be learned regarding the habits of our species. 



The Chrvsididffi are parasitic insects nourished in the cells 

 of various bees and wasps. The female Chrysid watches for a 

 chance to deposit her egg in a nest which is being stored by her 

 unwilling host, and the resulting larva either devours that of the 

 host or starves it by using up the food supply. From their 

 parasitic habits they are known as "cuckoo bees" or, more 

 properlv. "cuckoo wasps," and from their brilliant colours are 

 also called "ruby-flies." Our species are all small insects, seldom 

 over one quarter of an inch long, of a deep metallic blue colour, 

 varied with red, purple or green tints. The abdomen has fewer 

 visible segments than in the other wasps, and is excavated 

 beneath so that the wasp can roll itself into a ball, when attacked 

 by the insect whose nest it invades, and be quite safe against 

 injurv. Thev are exceedingly active insects, and are often seen 

 exploring the trunks of trees, the crevices of rocks, or the surface 

 of the ground for the nest of the species which they infest. 



The Bethvlidae are small ant-like insects which were formerly 

 classed as subfamilies of the Proctotrypidae, but which are now 

 considered as more closely allied to the wasps, and have been 

 placed as one of the families of the Vespoidea. The members 

 of the subfamily Bethylidae are parasitic upon coleopterous and 

 lepidopterous larvae, while those of the Dryininffi feed upon 

 immature Homoptera, chiefly fulgorids, membracids and jassids. 

 In both subfamilies the females are frequently wingless, and the 

 females of the Dryininae have curious chelate anterior tarsi, 

 probably to enable them to cling to the insects on which their 

 eggs are placed. 



The Tiphiidae are represented by only two species of rather 

 large shortlegged black wasps which belong to the genus Tiphia. 

 The members of the family, which was formerly included in the 

 Scoliidse, are parasitic upon the larvae of ground-inhabiting 

 beetles. 



The few remaining species of our Vespoidea belong to the 

 families Thynnidae, Myrmosidae and Mutillidae; the first two 

 families being considered by many authors as only subfamilies of 

 Mutillidae. These groups are very poorly represented in our fauna 

 and the few species which do occur are usually rare. The females 

 are all wingless and resemble ants in general' appearance, but the 

 males are winged and differ much in form from the females, and 

 are black while the females may be variegated in colour. These 



