BAG-WORM MOTHS 



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usually have a series of prolegs or false legs developed on 

 the abdominal segments. The more common number is 

 ten, four pairs located on the central abdominal segments 

 and one terminal pair. These are not homologous with the 

 segmentally jointed appendages of insects generally. They 

 stand out prominently and are fitted commonly with rows 

 of small hooks or teeth at the margin. The larvae are elon- 

 gate and generally cylindrical and are followed by a pupa 

 stage strikingly different from the larval stage and fre- 



FiG. ICO. — Bag worm (Thyridopieryx ephemercrformis): n, full-grown 

 larva; h, head of same; c, male pupa; d, female pupa; e, adult female; 

 /, adult male. All enlarged. (From Howard, Div. Ent., U. S. Dept. Ag.) 



quently enclosed in a cocoon. This is a quiescent stage. 

 The adult on issuing splits the pupal case along the dorsal 

 portion and crowds its way out. 



Bag-worm Moths. — Among the lower forms are the bag- 

 worm moths. These are forms in which the larvae construct 

 a case or bag of bits of leaves or twigs with which to protect 

 themselves. Almost parallel with the habit of the caddice 

 flies. One of the most common is the evergreen bag worm 

 {Thyridopieryx eyhcviercBJormis) . Its favorite food plants 

 are conifera, red cedar, and arbor vitse. It occurs com- 



