74 



The Dog-day Cicada, or Frosted Harvest fly, which is known under the name of 

 C. canicularis, as well as that given above, is by far the commonest species in Canada. It 

 is a large handsome fly, sometimes over two inches in length from the front of the face to 

 the end of the hemelytra. The head is black and prettily variegated with green and brown 

 markings ; it is very wide, short and transverse ; the eyes are prominent, and the 

 thorax is broad and also ornamented with green and brown markings. The 

 wings are transparent and slightly hyaline. The outer edge and the veins of the 

 basal portion are green for about one-third of their extent and deep brown for the 

 remainder ; towards the apex of each hemelytron there is a brown W shaped mark. This 

 insect, which is to be heard on hot days throughout the whole summer, is tolerably com- 

 mon in Canada, but is somewhat difficult to capture. In passing through the rocky 

 country between Lake Superior and Manitoba about the middle of last September, I heard 

 many of these flies trilling out their shrill notes. The specific name pruinosa = frosted, is 

 given on account of the newly-evolved imagines being thickly covered beneath their 

 abdomens with a white powdery matter, which gradually gets rubbed off as the insects 

 get older. 



In the United States this Cicada is carried off by large burrowing wasps or hornets 

 as food for their young. These wasps are exceedingly handsome and are called Stizus 

 grandis and S. speciosus. I have a specimen of the former of these which was captured 

 in the act by Mr. A. H. Moore in the Smithsonian grounds at Washington. It measures one 

 inch and three-quarters from the forehead to the tip of the abdomen, and possesses a large for- 

 midable sting with which these insects paralyze their victims previous to storing them away 

 as food for their progeny. In the American Entomologist, vol. 1, N.S., there is a most 

 interesting account of the instinct displayed by S. speciosus in availing itself of a favour- 

 able wind to transport its victims to its burrows, which, on account of their large size 

 compared with its own, it would be unable to do without some assistance. 



Cicada rimosa, Say. — The Creviced Harvest fly is the smallest species we have ; it 

 generally appears a few weeks previous to pruinosa, and in the United States at the same 

 time as C. septendecim, which it resembles somewhat and with which it has been frequently 

 confounded. It has the outer edge of the wings, parts of the legs and the edges of the 

 abdomen of a yellowish brown, but not so bright as in septendecim, and the eyes are 

 dark. In size, too, it is much smaller. 



Cicada septendecim, L. : the Seventeen-year Locust. — This remarkable insect, con- 

 cerning which so much has been written, is also said to have been found in Canada. It is a 

 slighter insect than C. pruinosa, and its colours are much brighter ; the body is black and 

 the eyes reddish orange, the legs and under-side of the abdomen are orange, as are also 

 the outside edges and veins of the wings. 



Fig. 84. 



