146 THE CANADIAN ENTOMOLOGIST. 



On 26th : " I went to-day to another swamp where I found quite a 

 number of aphides, all on the stems of alder, some so low down as to be 

 under the grass. There was also one butterfly flying, but I could not 

 catch it. I got, however, one egg, which I mail to Mrs. Peart, There is 

 a small Syrphus fly grub which devours the aphides far faster than does 

 Tarqumius. I took 6 from the twigs of aphides which I send you to-day. 

 These grubs stick the wool from the aphides upon their own backs, and 

 are often difficult to detect* 



"After second moult, I find the larvae crawling naked on the limb 

 seeking for fresh supplies of food ; then they again spin a web, which 

 they leave after the aphides are consumed. I do not think they spin 

 after third (the last) moult. They then go about very quickly. 

 There are four species of ants guarding the aphides on the alder, 

 and I find fewest Tarqiiinius larvae among those guarded by the black 

 and red ones I before told you of, though the butterflies do not seem 

 to fear them in the least. The female lays her eggs generally close to or 

 among a bunch of aphides, but occasionally on the leaf, if it rests on the 

 aphides. The latter do not feed upon leaves unless just at the 

 junction of them. On putting in a fresh supply for the larvae they at 

 once burrow under and devour the aphides from the under side, unless 

 after third moult, when the larvae eat roads through, but still from the 

 under side, their backs covered with wool from the unlucky aphides. I 

 think the wool prevents eating from above, for I noticed the larvae eat 

 the red aphides from cherry from the back, or wherever they seized 

 them." 



Aug. 30th : " Each stem has to be cleared of ants, some species of 

 which not only bite sharply enough to draw blood, but also sting, and cut 

 off with a knife, the slightest jar often knocking off the aphide5 and such 

 larvae as are not in webs. Then there is what I take to be a Syrphus 

 larva which has to be removed, as it devours twice as many aphides as 

 do the Tarqui?is. These lie under the aphides, often in a web of the 

 Tar quins, and are very difficult to find." 



Sept. 3rd : " Last night I saw a Tarquin just out of egg and watched 

 it for over an hour spinning a web close to and almost under a large 

 Syrphus grub. So I do not suppose these grubs injure the Tarquins. It 

 crawled under the mouth of the grub and over its back, without the least 



Syrphus-fly grubs. See Harris, p. 248. 



