7088 Insects. 



they are unable to withdraw them again quickly, frequently breaking 

 them off in their efforts to escape ; or when pulled violently away by 

 a bird or entomologist, their long, hair-like instruments may often 

 be seen sticking out of the stumps and trees they frequent. The stump 

 from which I took the first specimen I ever saw was so hard and 

 undecayed that I failed in making a hole in it with a strong knife deep 

 enough to ascertain what the Rhyssa is parasitical on, nor did I ever 

 succeed, though I made many attempts, in discovering what insect it 

 infests * Many people in Canada, ignorant of Entomology, suppose 

 that it is this ichneumon which kills the trees by " stinging" them, as 

 they term it, and accordingly destroy it when they have an opportunity; 

 and small holes in the bark of trees, made by some beetle allied to 

 Scolytus, have been pointed out to me as having been made by the 

 " sting " of this insect and that of Tremex Columba. Between the 

 anal segments of the female is a wide space filled by a loose, delicate, 

 pea-green membrane, inside which her ovipositor, measuring in some 

 specimens more than four inches in length, is partially coiled up, when 

 she is boring into a tree, in order to shorten it and therefore increase 

 its strength and stiffness. When the ovipositor is thus coiled up it 

 swells out the membrane to the size of a kidney bean, which it much 

 resembles in shape and colour, and the insect has then the most extra- 

 ordinary appearance that can be imagined ; and the first time I 

 observed one engaged in ovipositing, I was at a loss to decide what 

 this curious membranous bag could be. The females vary much in 

 size, and the males are but rarely seen. 



Family Formicid.e, Leach. 

 Formica Jierciilanea, Linn. (F. lignivora, Lair). Swarms about 

 Montreal, and in the woods north of the Ottawa, &c., tunneling through 

 dead trees in every direction, gradually reducing the interior to a mass 

 of dust. Wood in w^hich it has made its galleries has exactly the 

 appearance of timber which has been attacked by Teredo navalis. In 

 the interior of a hollow but still living balsam fir {Abies balsamea) 

 which had been attacked by this ant, and snapped across by the wind, 

 I found the hard knots lying loosely amongst the dust and debris^ 

 having been gnawed all round to remove the soft wood, just as a dog 

 would gnaw the flesh off a bone. " Misfortune," it is said, "makes 

 one acquainted with strange bedfellows," and certainly Formica hercu- 

 lanea was not one of the least disagreeable with which I was compelled 



* Ihave little doubt of the Rhyssa being parasitic on the larva of Tremex Columba ; 

 Rhyssa persuasoria is parasitic on Sirex juvencus. — Frederick Smith. 



