82 THE CANADIAN ENTOMOLOGIST. 



pressioiis ; maxillary palpi long, 5-jointed, labial palpi 3-jointed. Ovi- 

 positor concealed in a groove beneath, springing from the last segment, 

 long and very slender. It is ordinarily concealed in a channel beneath 

 the abdomen, but is capable of being extended, for which purpose it can 

 be curved at the base. The terebra is formed like that of Urocerus. The 

 anterior lobe of the mesothorax is wide and extended back to the scutel- 

 lum, while the side lobes are very small. The scutellum is widened and 

 large. Anterior tibiae with one end spur, simple in the males, dilated and 

 incised in the females. Tarsi 5-jointed in males, 3-jointed in females." 



Having now some knowledge of the genus, we can proceed to con- 

 sider the species. I have not been able to examine a catalogue of Euro- 

 pean Hymenoptera, but the various authors consulted mention two 

 species. One of these is O. coro?iatiis Latr., the type of the genus; the 

 name of the other is not given. Lucas, loc. cit., briefly describes O. cor- 

 onatjis as "12 m. long, of a shining black, with the abdomen of a tawny 

 red ; the two first segments black, and the last ornamented with a white 

 spot in the males only." This description would apply equally well to a 

 specimen taken by Mr. Fletcher in Vancouver Island, and the figure given 

 might also answer for this specimen. It may, however, have other features 

 sufficient to readily distinguish it from our species. It inhabits chiefly the 

 central part of France and some portions of Germany. 



The two European species were for a long time the only representatives 

 of the genus known to Entomologists, and the American species were 

 apparently first brought to their notice by Harris. In his " Catalogue of 

 the Insects of Massachusetts," published in 1833, he enumerated three 

 undescribed species, and in the second edition, 1835, he gave to them the 

 following names : O. hcemorrhoidalis, O. maurus dind O. affitiis ; signify- 

 ing respectively the red-tailed, the dark-coloured, and the allied. No 

 description of them was published by him until 1841 in his Report on 

 Injurious Insects. In 1838, Newman (Ent, Mag., vol. v., page 486) 

 described the first of these insects under the name of O. terminalis, and 

 Westwood (Zool. Jour., vol. v., page 440) described the second in 1835 

 as O. Sayi, having received a specimen from Say. No additional species 

 were recorded until 1879, when Cresson (Trans. Am. Ent. Soc, vol. viii,, 

 page 48) described O. occidentalis from Colorado and Nevada, and O. 

 Mexicamis from Mexico. 



All these species have been described from single specimens, or at the 

 most fr6m a very limited number, and the insects have always been rare, 



