112 LEAF-MINING INSECTS 



and the dorsum of the abdomen is provided with backward- 

 pointing bristles. The tenth abdominal segment has promi- 

 nent lateral projections ending in stout, straight, lateral 

 spines. 



At the time of the emergence of the adults the pupal shells 

 are protruded from the cocoons. 



The adult. The adults of this genus are wont to have 

 rather decided markings often of brown, black and silvery 

 white. The basal segment of the antennae is extended to 

 form an eye cap. The head is tufted and the face is smooth. 



The ribbed-cocoon maker of apple, Bucculatrix pomifoliella, 

 is undoubtedly the one of our species most generally known. 

 This species is distributed very generally in eastern Canada, 

 and in the United States from Maine to Texas. Though 

 usually not a serious pest, it becomes at times locally abun- 

 dant. Like the cigar case-bearer and the trumpet miner, it 

 seems to prefer the imported and cultivated apple to the 

 native pome fruits with which it originally contented itself. 



The adults from hibernating pupae emerge when the 

 apple leaves are unfolding in May in the northern states. 

 They are small (2 to 3 mm. in length), in color light brown 

 and marked on each wing with a dark brown spot. The 

 moths pair about three days after emergence and soon the 

 eggs may be found among the hairs on the lower surface 

 of the leaves, especially towards the center of the leaves. 



After six to ten days the tiny caterpillars bore directly 

 through the egg-shells and cuticle and up through the paren- 

 chyma to the tissue just below the upper cuticle. For about 

 a week the larvae remain in the leaves tunneling out narrow, 

 brown, gradually widening serpentine mines. When the 

 larvae are 2 to 3 mm. long and the mines about 2 cm. long 

 they cut a slit through the upper cuticle and come out on 

 the leaf. There they soon spin small circular or oval silken 

 webs, their first moulting cocoons. Taking a position on 

 this network the larva bites a small hole near its edge and, 



