443 



FARMERS' INSTITUTES. 



Of these flies, I write as follows ia my 

 Manual, p. 319 : 



" There are two other species of this 

 family, Mallopliora Orcina and M. bom- 

 hoides, which differ greatly from those 

 mentioned above (species of Asilus, Erax 

 and Proinaclius, which are dark gray or 

 black, with long slim bodies thinly cov- 

 ered with hairs). They look more like 

 bumble-bees, for which they have been 



Mallophora Orcina. mistaken." 



M. Orcina, the smaller of these Southern bee-killers, is about one inch 

 long, and expands (see figure) If inches. M. bomboides is a little larger. 

 Both are yellow with black bands, and are densely clothed with hairs. The 

 beak is very strong, and it is with this that these marauders are enabled to 

 pierce the thick crust, and suck the life-blood of bee or other insect. It will 

 be remembered that these, with all two-winged flies, belong to the order 

 Diptem. All of these insects have their mouth-parts modified into a strong 

 beak with which they pierce and suck. Thus it were more proper to say, 

 perhaps, that the robber-flies, mosquitoes, and horse-flies, stab or pierce, than 

 to say that they bite. These flies have a very strong beak, large strong feet 

 (see Manual, Figs. 175 and 176, p. 319), and very prominent eyes. As inti- 

 mated by Messrs. Hill and Tufts, these are very ferocious insects. Indeed, 

 they are very lions among the insect tribes, or they would not dare attack 

 the honey-bees. With their close allies, the asilus flies, they do much good, 

 and we have only to regret that both these flies have the unwelcome habit of 

 attacking and killing bees. It is to be hoped that they will never be numer- 

 ous enough to cause serious anxiety. If they do, we must resort to hand- 

 -catching by aid of handle-nets. 



MOEPHOLOGY OF THE LEGS OF HYMENOPTEROUS INSECTS.* 



BY PROF. A. J. COOK, AGRICULTURAL COLLEGE, MICHIGAN. 



According to our modern philosophy regarding the origin and develop- 

 ment of animal organs and organisms, we should look at such organs as are 

 much used in the animal economy to find extremes in modification. Thus 

 among mammals the teeth are most modified and very important in system- 

 atic mammalogy. For like reason the ornithologist looks to bill and feet in 

 his study of families and genera. With the laws of variation and adaptation 

 before us, we should expect to find modification carried to extremes among 

 hymenopterous insects. The life functions of these insects are so wonderful 

 and varied that a maximum differentation of organs and structure is required 

 for their execution. The chief tools used by these hymenopterous are the 

 legs and mouth organs, and it is to the former that I invite attention. 



* This paper was read before American Asbociation for the Advancement of Science, at the New 

 York meeting, August, 1887. 



