204 



THE STUDY OF INSECTS 



This is a large family; about two hundred North American species 

 have been described. 



The white-blotch oak-leaf miner, Phyllonorycter hamadryadella. — 

 This little miner infests the leaves of many different species of oaks, and 

 is very common throughout the Atlantic States. The mine is a whitish 

 blotch mine in the upper side of the leaf, and contains a single larva ; but 

 often a single leaf contains many of these mines (Fig. 352). The young 

 larva is remarkable in resembling more the larva of a beetle than the 

 ordinary type of lepidopterous larvae (Fig. 352, 6). It is nearly flat; the 

 first thoracic segment is much larger than any of the others; the body 

 tapers towards the hind end; and there are only the faintest rudiments 

 of legs discernible. The larvae molt seven times. At the seventh molt 

 the form of the body undergoes a striking change. It now becomes 

 cylindrical in form, and the fourteen feet are well developed. It spins a 

 cocoon, which is simply a delicate, semi transparent, circular sheet of 

 white silk, stretched over a part of the floor of the mine. The pupa is 

 dark brown in color, and bears a toothed crest upon its head (Fig. 352, n, 

 o). The moth is a delicate little creature, whose wings expand a little 

 more than \ of an inch. 



Family Coleophorid^; 



Moths with a smooth head, without ocelli, and without maxillary 

 palpi. The labial palpi are of moderate size. The antennae are held 

 extended forward in repose. The wings are very narrow. 



The larvae are usually 

 leaf-miners when young 

 or feed within seeds; 

 later, with few excep- 

 tions, they are case- 

 bearers. 



All of our species be- 

 long to the genus Cole- 

 ophora, of which about 

 ninety species have been 

 found in this country. 

 The two following spe- 

 cies are those that have 

 attracted most attention 

 on account of their 

 economic importance. 



Fig. 353. — Cohophora malivorella: a, apple twig showing larval cases Ine piStOl Case- 



and work, on leaves; b, larva; c, pupa; d, moth; b, c, d, enlarged. (After bearer, ColeOphOYQ, tUdll- 



vorella. — The larva of 

 this species infests apple especially but is also found on quince, plum, and 

 cherry. The larvae hatch in mid-summer from eggs laid on the leaves 

 and eat little holes in the leaves. They soon construct little pistol-shaped 

 cases composed of silk, the pubescence of leaves, and excrement (Fig. 353). 

 The larva projects itself out from the case far enough to get a foothold 

 and eats irregular holes in the leaf, holding the case at a considerable 

 angle with the leaf. About September first the larvae migrate to the 

 twigs where they fasten the cases to the bark and hibernate till April. 



