394 Report of the Department of Entomology of the 



LIFE STAGES OF malinellus. 



Egg. — This is apparently not distinguishable from that of padellus. 

 The egg masses are also of a similar appearance, Plate XXXVIIl. 



Larva. — The mature caterpillar is apparently not different in its 

 external characters from the padellus larva. The caterpillars reared 

 on apple seedlings varied much in coloration, and the majority of 

 them were yellow and lacked the median dorsal and sub-dorsal 

 shaded areas which usually prevailed with "^he preceding species. 

 Plates XXXIX and XL 



Pupa. — Light orange yellow or brown, with the extremities 

 sometimes dark. Length, 6-8 mm. Plate XL. 



Cocoon. — White and more densely woven than with preceding 

 form. Cocoons are thickly massed in the tent. Plate XLL 



Adult. — Similar to the light form of padellus and indistinguishable 

 from it. Plates XLI and XLII. 



LIFE HISTORY AND HABITS. 



Oviposition occurs principally during the latter part of June or 

 during July, according to latitude and seasonal conditions, and 

 hatching takes place in early autumn. The young larvae at this 

 season are inactive and remain sheltered through the winter under 

 the protecting crust of the eggs. They abandon their winter quarters 

 as the first leaves begin to unfold in the spring, making their 

 exit through one of several tiny holes in the covering of the egg 

 mass. The young caterpillars assemble among the tender leaflets* 

 of an adjacent bud and those of malinellus on apple bore into the 

 parenchyma, beginning at the edge and usually near the apex of 

 the leaf. As many as a dozen of the insects may exist as a colony 

 within the pulpy substance of a single leaf. Within a few days 

 after their entrance the leaves turn reddish at the points of injury, 

 and those more severely mined may wither and die. Towards the 

 end of the time of blossoming the caterpillars cease to burrow and 

 feed openly on the leaves, concealing themselves with a greyish web. 

 With the need of more food they extend their webs, seizing and 

 involving fresh leaves in the common nest, on which they feed. 

 Having destroyed the foliage on one branch they migrate " en masse " 

 to another, and in severe attacks the trees may be defoliated and 

 completely covered with a veiling, which becomes discolored by 

 stains from the enclosed fragments of leaves and the dust-like 

 excremental particles of the insects. On reaching maturity the 

 larvse spin their cocoons in contact with each other and, according 

 to Mokshetsky, there may be during very destructive outbreaks 

 as many as fifteen hundred cocoons placed side by side in regular 

 rows within the silken tent. The moths make their appearance 

 during the latter part of June or early July, and egg-laying commences 



