116 INDIRECT INJURIES CAUSED BY. INSECTS. 



been called to the mischief, under their direction, my lamented friend 

 Professor Audouin was, at the period of his untimely death, which Ento- 

 mology so deeply deplores, engaged on a fine work embracing a complete 

 history of the insect, with figures of it in every state, and an account of 

 the best means of destroying it. The worst pest of the vine in this 

 country is its Coccus (C. vitis). This animal, which fortunately is not suffi- 

 ciently hardy to endure the common temperature of our atmosphere, 

 sometimes so abounds upon those that are cultivated in stoves and green- 

 houses, that their stems seem quite covered with little locks of white 

 cotton ; which appearance is caused by a filamentous secretion transpiring 

 through the skin of the animal, in which they envelop their eggs. Where 

 they prevail, they do great injury to the plant by subtracting the sap from 

 its foliage and fruit, and causing it to bleed 1 ; and, to close the list without 

 extending it by alluding with M. Walckenaer to the insects only occa- 

 sionally injurious to the vine, you are perfectly aware of the eagerness 

 with which wasps, flies, and other insects, attack the grapes when ripe, 

 often leaving nothing but the mere skin for their lordly proprietor. 



There are some of these creatures that attack indiscriminately all fruit- 

 trees. One of these is the Cicada septendecim (so called because, ac- 

 cording to Kalm, it appears only once in seventeen years 2 ). The female 

 oviposits in the pith of the twigs of trees, where the grubs are hatched 

 and do infinite damage both to fruit and forest-trees. 3 Birds greedily 

 devour them ; and a curious fact is mentioned by Dr. Harlan of Phila- 

 delphia (who confirms their septendecenary appearance), that young 

 fowls which eat them lay eggs with colourless yolks. 4 Another, the 

 caterpillar of the butterfly of the hawthorn (Pieris crat&gi), which, in 1791, 

 in some parts of Germany stripped the fruit-trees in general of their 

 foliage. 5 In France also, in 1731 and 1732, that of a moth, which seems 

 related to the brown-tail moth (Porthesia auriftua), whose history has been 

 given by the late Mr. Curtis, was so numerous as to occasion a general 

 alarm. The oaks, elms, and white-thorn hedges looked as if some burning 

 wind had passed over them and dried up their leaves ; for, the insect 

 devouring only one surface of them, that which is left becomes brown and 

 dry. They also laid waste the fruit-trees, and even devoured the fruit, 

 so that the parliament published an edict to compel people to collect and 

 destroy them ; but this would in a great measure have been ineffectual, 

 had not some cold rains fallen, which so completely annihilated them, 

 that it was difficult to meet with a single individual. 6 In Germany, ac- 

 cording to M. Schmidberger, the larvae of the following moths, Porthesia 

 chrysorrhcea, Clisiocampa neustria, Hypogymna dispar, Episema cceruleo- 

 cephala, Yponomeuta padella, and especially Cheimatobia brumata, which he 

 calls the most ruinous of the whole, are all more or less injurious to fruit- 

 trees generally. 7 In the north of France, as we learn from Mr. West- 

 wood, one of these caterpillars, that of the small ermine moth (Yponomeuta 



1 According to M. Walckenaer, in his elaborate and learned Essay on the Insects 

 injurious to the Vine (Ann. Soc. EnL de France, iv. 687.) it is the Coccus adonidum 

 which is injurious to vines in hot-houses in France, while the Coccus vitis attacks 

 those in the open air. 



Travels, ii. 6. 5 Collinson in Philos. Trans, liv. x. 65. 



4 Trans. Ent. Soc. Lond. i. proc. xxx. 



Rosel, I. ii. 15. e Eeaum. ii. 122. 



* KOllar on Ins. inj. to Gardeners. &c. 190 229. 



