52 



works on the North American flora, elaborately describe the different orders, genera 

 and species of plants. I was, therefore, glad to find the information desired in a French 

 work published in Quebec, Abbe Provancher's " Petite Faune Entomologique," just then 

 completed to the end of the order Hymenoptera, which comprises the bees, wasps, ants, 

 ichneumon-flies, saw-flies, etc. After some little labour, I succeeded in ascertaining in 

 that too modestly narnqd Fauna, both the generic and specific names of my insect, — 

 Megachile melanophcea, i.e. the black-brown Leaf-cutter. 



The name of the genus having thus been obtained, it was easy to gather more 

 information in works treating of Hymenoptera, especially in those describing the labours 

 of the parent bees on behalf of their offspring. Thus I found that the habits of the 

 Leaf-cutters were observed and described by the French naturalist Reaumur, as early as 

 the beginning of the last century. Mr. E. Baynes Reed, in the Second Annual Report of 

 the Entomological Society of Ontario (p. 24), and Mr. W. H. Harrington in the XVIth, 

 (p. 53), have given the principal facts of their history, how they cleverly cut circular 

 pieces of leaves with their mandibles, and use these pieces in the construction of the cells 

 of their nests. 



Megachile centuncularis, L., which is spread all over the continent of Europe and 

 also occurs commonly in Canada, chooses for its nest either an old post or decaying tree 

 or the soft mortar of an old wall, or again burrows in the ground (Smith, Brit. Museum 

 Cat. T. p. 174). The powerful mandibles are of course the instruments used to dig the 

 gallery in which the cells are then placed end to end from the bottom up to its mouth. 

 The bees also sometimes take advantage of cavities which they find suitable for their 

 purpose, such as a nail hole, or the deserted tunnels of wood-borers. I have seen 

 repeatedly come in ana out of such holes the active little M. optiva, which is easily 

 recognized by its red ventral brush, and Gnathocera cephalica, Prov., a bee very closely 

 allied to the Leaf-cutters, but which at last stopped the aperture with mud, and probably 

 like other bees builds its cells of that substance. I was not able in the latter case to 

 ascertain what was the material of the nest itself, as it was in a post of a public bridge. 

 But I opened, after its completion, the nest of M. optiva, which was in a board of a shed 

 and found it to be composed of several rows of cells packed up side by side, the cavity 

 being too wide for a single row. The insect seemed, however, to have always made as 

 many cells as possible in one line, according, no doubt, to its habit of doing so in the 

 straight galleries which it digs itself. The cells were formed with morsels of leaves and 

 flowers of scarlet runners. The aperture itself, which was just large enough to admit the 

 insect, was stopped up with about twelve round pieces laid on each other, each slightly 

 larger than the hole, but forced in so as to fit perfectly, the last one outside being a red 

 one. The nest contained about twenty cells which I was very careful to secure and pre- 

 serve in the hope of procuring the perfect insects, and if possible, by some happy 

 chance, to obtain in the number a male, that sex of this species still being unknown to 

 science. My hopes, however, were doomed to disappointment. After the return of 

 spring, weeks succeeded weeks, but the cells still remained closed ; and finally, instead of 

 the bees, there issued from them through tiny holes, scores and scores of a Chalcidite, 

 Semiotellus cuprcms, Prov. These small parasites had not spared a single one of the 

 larvae for which the mother Megachile had on the preceding summer provided with so 

 much solicitude and industry. 



On a subsequent occasion, I found the broken stem of a sun-flower in the hollowed 

 pith of which some Leaf-cutter had built half a dozen cells with morsels of rose leaves. 

 These pieces were much looser than those in the nest of M. optiva, and made the cells 

 appear much larger, so that I expected to see much larger bees come out of them. They 

 proved, however, to be of a rather smaller species, M. brevis, Say (Fig. ^8), of which I 

 have found the males very abundant, but have never been fortunate enough to secure 

 a female. From this nest I obtained only males, two of them, and — four parasites, again 

 Chalcidites, but much larger than in the preceding case, so that each had required a whole 

 Megachile larva for its subsistence. These parasites were two males and two females of the 

 pretty wasp-like Leucospis a finis, Say ; other species of the same genus have also beea 

 found in Europe infesting Megachile nests. 



