96 THE CANADIAN ENTOMOLOGIST. 



Reaumur (writing before the middle of the last century), in publishing 

 the results of his investigations on the ichneumons, divided these flies into 

 two classes, according to the position of the tarriere, or augur, of the 

 female. The first class comprised the true ichneumon flies, but the second 

 consisted of those now included in the family Uroceridce. He says: "The 

 females of the ichneumons placed in the second class have also, like the 

 others, an augur, but they carry it applied against the under side of the 

 body ; ordinarily its end does not project, or projects but little, beyond 

 that of the body ; it is lodged in a sheath made of two pieces hollowed 

 like a gutter, and adheres to the body for the first half, and sometimes for 

 more than the half of its length." He regarded them " all as flesh-eaters 

 when they are in the form of worms," adding, " if, however, any fly 

 resembling an ichneumon is found which in the grub form does not feed 

 upon some other insect, it can still be regarded as an ichneumon, but 

 would have to be excepted from the general rule." The old fallacy that 

 exceptions prove the rule has not been fulfilled in respect to these so-called 

 ichneumons, and they have long since been divested of this title. In 

 describing a large species received by him from a traveller in Lapland as 

 one of the largest he had seen, he expresses much astonishment that such 

 a cold country should furnish a larger species than the mild climate of 

 France, because from warm countries, especially from tropical ones, came 

 the largest insects known. The species in question was Sirex gigas, which 

 much resembles in size and coloring our large Pigeon Tremex hereafter 

 described. A few years later, De Geer (a Swede) published a valuable 

 series of Memoires, confirming and supplementing those of Reaumur. One 

 of these treats of ichneumons, which are divided into nine classes, accord- 

 ing to the shape of the abdomen and the manner of its attachment to the 

 thorax. The first class comprised : " The ichneumons of which the 

 antennae are conical threads, or diminish little by little in size toward the 

 tip, ending in a fine point ; of which the body is not attached to the thorax 

 by a thread, but toward the base is of the same or nearly the same size 

 as the thorax, and terminates in a horny, elongated point in the form of a 

 short tail. This tail must not be confounded with the augur and its sheath • 

 it is only a prolongation of the body. The large ichneumon which M. de 

 Maupertuis brought from Lapland and gave to M. de Reaumur, is of this 

 class." This observant naturalist calls attention to the curious mechanism 

 on the hinder wing of these insects, by which the wings, when extended, 

 are so connected as to form a single surface, thus sustaining a more 



