36 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



pressed and concave, the hollow being oval and following the out- 

 line of the margins; the bottom side or base is flat. The surface is 

 rough and sculjotured into irregular polygons with from three to six 

 sides. The eggs are adhesive, hard, visible to the naked eye, but 

 minute, measuring 0.63 by 0.38 mm., and are deposited singly. They 

 differ in aspect from those of the peach borer, and also are usually 

 lighter in color and not as large and stout. They are rather more 

 difficult to find in nature. 



At present the length of the period of incubation is not well known. 

 Mr. Quaintance records it as 7^ days in the month of September, 

 latitude of AVashington, D. G. Upon hatching, the little larva 

 cuts its way through the anterior end of the egg, leaving quite a 

 large exit hole in the egg shell, which retains its shape and place 

 until it weathers off. 



The eggs Avere first observed in nature by Bailey (18T9) ; he found 

 a cluster of them on the under surface of loosened plum bark, about 

 G inches above the roots. Usually, however, they are deposited 

 singly along the trunk of the tree, being placed in crevices, openings, 

 or roughened places. Sometimes a few are placed on the ground or 

 high ujj in the tree on twigs or leaves, but the majority are de- 

 posited on the main trunk of the trees. The number deposited by 

 a single female is unknown. Moths kept in confinement refuse to 

 mate, and the female deposits few eggs or none at all. To determine 

 the number resort is therefore made to dissection. Mr. Quaintance 

 dissected two fertile females after death, and found 305 perfect eggs 

 in one and 296 in the other, in addition to numbers of small unde- 

 veloped ones. Each moth had deposited a few eggs before dying, 

 which were included in the count. Dissection of the ovaries of a 

 sterile moth yielded but 58 perfect eggs, but there were present 

 many undeveloped ones. Until more dissections are made the evi- 

 dence on this point remains inconclusive. 



The larva. — AATien the larva hatches it is very small, and especially 

 hard to detect with the naked eye because of its dull white color. It 

 is an ordinary caterpillar, bearing the usual setpe and number of pro- 

 legs, and in its earlier stages is almost indistinguishable from the 

 young larvsc of the peach borer. However, after molting once or 

 twice it acquires a different aspect, which together with a more 

 pinkish and translucent color makes it somewhat more distinct. 

 Throughout all its life it remains about the same color — various 

 shades of creamy white — and Ha'cs concealed under the bark. The 

 following is a description of a full-groAvn larva, or instar VI: 



Lengtli, 20.") mm., averase. (Jreatost \vi(UIi. :>.4 mm. Width of head, 1.04 

 mm., averajio. Normal for tho famil.v : Body soiled cream color, immaculate, 

 with the usual more or less generalized characters. Head yellowish brown, 



