THE GRAPE SCALE. 



117 



and an equally brief period of activity of the winged male, is passed 

 under the protection of a waxy covering, closely applied to the host 

 plant. The female is wingless throughout her life. The adult 

 winged male appears in June. The winter is passed by the insects in 

 a nearly full grown condition. Our observations show that there is 

 only a single brood of larvae each year. It also appears that this 

 species does not deposit eggs, as has been thought, but that the 

 female is viviparous. 



Some newly born, larvae (fig. 26) 

 were placed on a grape cane in 

 order to ascertain the length of the 

 active stage. The crawling "lice" 

 were kept under occasional observa- 

 tion and at the end of 24 hours all were 

 still moving, but after 48 hours all lice had 

 settled down and had already begun the 

 excretion of the white waxy covering. The 

 scale formed over the young insect is 

 whitish in color and appears to have two 

 rings on its dorsal surface. The edge of the 

 scale is closely cemented to the bark of the 

 twig. 



Many larvae were examined to ascertain 

 how fully the lobes were developed. When 

 one day old, well-developed median lobes 

 were found to be present. 



DESCRIPTION. 1 



Scale of female (PI. XVIII, fig. 2).— Yellowish- 

 brown, slightly lighter than the bark of the vine, 

 diameter 1.1 to 1.7 mm., circular and comparatively 

 flat, exuviae bright yellow, subcentral. 



Scale of male (PI. XVIII, fig. 2).— Elongate, length 

 0.9 to 1.0 mm., width 0.5 mm., exuvise to one side, 

 slightly darker and more convex than female scale. 



Adult female (PI. XVIII, fig. 3).— From 1 to 1.4 mm. 

 in length, oval. Anal plate 0.4 mm. broad at base 

 by 0.23 mm. long. Median lobes prominent, more or 



less parallel, slightly diverging at tip, notched on each margin, with inner notch fairly 

 prominent and slightly elevated ; lateral lobes wanting or rudimentary, as is the case 

 with ancylus; two distinct lateral incisions present; paraph yses of first incision conspicu- 

 ous, inner the largest, pear-shaped; paraphyses of second incision much smaller; 

 plates minute, obscure; spines on dorsal surface strongly developed, one on median 

 lobe, one cephalad of each incision, and one halfway to the penultimate segment, 

 ventral spines smaller and lateral of dorsal spines; anal opening small, circular, about 

 two and one-half lobes length from tip of median lobes; paragenitals, median 0-4, 

 anterier laterals 4-9, posterior laterals 3-7; dorsal pores present in three rows, first con- 



1 Prepared by Mr. E. R. Sasscer, of the Bureau of Entomology. 

 71419°— Bull. 97—12 9 



Fig. 26.— The grape scale: Newly 

 hatched larva, ventral view, show- 

 ing legs; A, antenna; B, anal seg- 

 ments. Much enlarged; A and B 

 more enlarged . ( O riginal. ) 



