No. 6. DEPARTMENT OF AGRICULTURE. 327 



six weeks. They leave for their meals at regular times and return 

 in processions. When fully mature they measure two inches, are 

 covered with hairs and very varigated in color, yellow and blue lines 

 predominating- along the sides, while the lower surface is black and 

 the middle of the back ornamented with a white baud. Pupation 

 takes place m some hidden spot in the cracks of the wall or under 

 boards where the yellow silken cocoon is spun. In two or three 

 weeks the reddish-brown moths come forth, pair and deposit clus- 

 ters of eggs along the twigs of the trees covering them with a viscid 

 varnish-like liquid to protect them against the cold of the winter. 



During very wet weather the caterpillars are destroyed in large 

 numbers by bacteria; there are also a number of primary, secondary 

 and tertiary parasites which decrease the number of these voracious 

 caterpillars considerably. I found the most effective remedy in the 

 careful watching of the ends of the branches and the immediate re- 

 moval of cutting or smoking, but the spraying with Paris Green or 

 kerosene emulsion never fails, if repeatedly applied. 



The Oyster-Shell Bark-louse (Mytilaspis pomorum), appeared in 

 large numbers on shade trees, apparently killing many of them, but 

 a liberal use of whale oil soap mixed with coal oil completely de- 

 stroyed the pest and all the trees under my observation assumed 

 their accustomed vigorous growth. 



Unfortunately, the Peach Twig Borer (Aoarsia lineatella) has also 

 made its appearance among us. I first observed the larvae of this 

 moth in the beginning of April on the new leaf shoots. They are of 

 a yellowish-brown color acd about 2 mm. long. They had eaten into 

 the shoot as far as the pitch and in some cases burrows, varying in 

 length from one-fourth to one and one-half inch, were found near the 

 petiole. I noticed them again in the fall, hidden in burrows of the 

 bark near the crotches of the branches of the peach; in this condition 

 they seem to hibernate. Some of the adult larvae reach a length of a 

 half an inch and become reddish in color; it spins a very loose cocoon 

 in the leaves of the tree and turns into a good sized chrysalis, from 

 which it emerges in a week or ten days a full fledged moth of beauti- 

 ful dark gray color with dark spots on the forewings. Its width is 

 about half an inch. Since but comparatively little is known about 

 this insect, it is rather difficult to detect it and yet they may do con- 

 siderable damage. I found quite a large number of peach fruit 

 mined, the peaches having been bored into a little wa}' near the stem. 

 The best method of preventing the injuries of this insect is to look 

 carefully for the comparatively large size of the ogg and its strildng 

 irridescent appearance, generally found at the base of the petiole, 

 and to clear the tree by scraping or by a thorough soaking of the 

 bark with a solutioo of Paris Green. 



The most aggravating insect of the year was the San Jos^ 



