82 THE REPORT OF THE No. 36 



Cassida viridis appeared in this country a few years ago. It feeds on the 

 Burdock and lies exposed on the plant. A curious provision is made to preserve 

 the larva from the heat of the sun, and to render it unattractive to predacious in- 

 sects and birds. By a fork-like appendage to the anal segment, the foeces are 

 retained and supported over the dorsal parts of the larva, and form a protective wad, 

 or shield. 



The Pupa. In the month of September, larvae of the Saw-fly^ Cinibex Am- 

 ericana, may sometimes be seen curled up, helix-fashion, on the ground, under the 

 trees on which they fed. It will generally be found that they are parasitized — 

 victims of Opheltes glaucoptenis. They may have strength remaining to enable 

 them to creep into some retreat; they may even attempt to spin the cocoon in 

 which under normal conditions, they would spend the winter months; but they 

 fail. Within them is the foe that is exhausting their vitality. This creature 

 undergoes the pupal change within "Ihe frame of its host, and, at length, bursts from 

 it as a perfect fly. 



The fine ichneumon Tragus fulvipes undergoes the pupal stage within the 

 pupa of the beautiful butterfly Papilio troilus. 



I may cite the following as a remarkable instance of the instinct of a larva 

 about to undergo the pupal change : — There was a needle-book, formed of alternate 

 leaves of white and golden flannel, lying open on a shelf in my study. One night 

 a larva of Samia cecropia escaped from the box in which it had been brought to 

 me, and disappeared. Sometime afterwards I found that it had spun a cocoon 

 in the needle-book, and had fastened a white fold on one side of its cocoon, and 

 a yellow fold on the other. To disguise its work more effectually it had secured 

 in the meshes of the cocoon, frayings of the white flannel on the one side, and 

 frayings of the yellow on the other. 



Volumes might be written upon the adaptations in structure which fit the 

 insect for its environment, which enable it to supply its wants, and which ensure 

 the perpetuation of. its species. The Naturalist delights to look into these things. 

 Considering them he feels, as David felt, that the Divine Designer of the Universe 

 "hath so done His marvellous works that they ought to be had in remembrance." 



" The melancholy days" have now come — "the saddest of the year ;" but we 

 still can find pupge of insects in their snug retreats; and we know that, when 

 "Heaven shall repair her rural seat," objects of beauty will burst from cocoon and 

 chrysalis, to gladden the hearts of the beholders. 



THE ACARINA, WITH A HOST INDEX TO THE SPECIES FOUND IN 



ONTARIO. 



By Tennyson D. Jarvis, Ontario AptRtcultural College, Guelph. 



There is probably no more widely distributed order of Arthropods than the 

 Acarina; in economic irnportance there is none of greater value; and within the 

 range of the whole animal kingdom there is no study so varied and fascinating 

 as that of the Acarids, commonly termed Mites. The relation of these to other 

 Arthropods has never been clearly defined, but in many respects they bear a close 



