THE GRAPE-LEAF SKELETONIZER, 



81 



Ms^: 



mm. and the miniinum 0.31(5 mm. The avora<2;e size of the Q^ii is 

 0.5G6 mm. by 0.341) mm. 



The eggs are dei^osited on tlie nnder.side of the knaves in chist.ers, 

 and from 12 clusters counted, 

 the minimum contained 7 eggs, 

 the maxinunn '2()0, the average 

 fluster containing 107.9 eggs. 

 Observations on l.OH.") eggs 

 gave the average length for 

 the e<]^g stage as 7.92 days, 

 Avitli a maximum of 9 days 

 and a inininuun of 7 days, tlie 

 average mean temperature for 

 the period of incubation of the 

 \arious eggs being 77.5° F., 

 with cloudy weather prevail- 

 ing. The eggs under observa- 

 tion were from the .second 

 generation of moths, and the 

 length of the stage would probably be somewdiat greater for the first 

 generation on account of lower temperature. 



Fig. l.j. — The grapc-U... ;..... r (Iluni- 



siniu (iiiicricana) : a. Egg, greatly enlarged ; 

 1). cluster of eggs in natural position on 

 leaf. (Original.! 



LAK\ A. 



Fhst instar. — Body yellowish-white, translucent. Head similar in 

 color to body, retractile, broader than body, Avhich gradually tapers. 

 Segments 2-13 with a transverse median row of spinelike bristles, 

 about 0.2 mm. in length, extending to Venter on each side; whitish 

 when viewed under a ?,-inch objective, but the dark-colored joints 

 cause them to ai)i)ear blackish under a small magnification. Thoracic 

 feet small, pointed, color similar to body; abdominal feet small, 

 visible only as small Avartlike protuberances. Length, 1-1.25 mm.; 

 width of head, 0.18-0.25 nnn. (variable). 



S('<o)i<1 iiistdv. — Body dilute-yellow, head retractile, darker, eyes 

 and mandibles dark brown. Tubercular areas now distinct under a 

 §-inch objective as a transverse row of wartlike clusters of whitish, 

 segmented bristles about 0.2 nnn. in lengtli, witli apex, joints, and 

 bulb at base of the bristles black. Ail the segments laterally, and 

 dorsum of the anterior and posterior segments with long, wdiitish. 

 segmented hairs about 0.75 mm. in length. Thoracic feet small, 

 j)ointed, dilute-brownish; abdominal feet, more distinct now, ai)pear- 

 ing as small stumplike projections. Length, l.(»(»Ct-2 mm.; width of 

 head, 0.283-0.333 mm. 



Third inntar. — Body orange-yellow, head retractile, dilute-bi'own, 

 eyes and mandibles brownish-black. Segments 2-13 show wartlike 



