580 AN INTRODUCTION TO ENTOMOLOGY 



Schierbeck ('i6 and '17) proposes still another terminology for 

 the setae, applying a Latin name to each. 



Most caterpillars, except, as a rule, the larvas of butterflies, 

 spin a cocoon. In some instances, as in the case of silk-worms, a 

 great amount of silk is used in the construction of the cocoon; in 

 others the cocoon is composed principally of the hairs of the larva, 

 which are fastened together with a fine web of silk. 



The pupae of the Lepidoptera are typically of the obtected type; 

 that is, the developing wings, legs, mandibles, maxillae, and antennas 

 are glued to the surface of the body (Fig. 718); but in some of the 

 more generalized forms these appendages are free. In the Micro- 

 jugate, which are provisionally in- 

 cluded in this order, these append- 

 ages are free, the pupae resembling 

 those of the Trichoptera ; but in the 

 Hepialidas the appendages are glued 

 to the surface of the body as in the 

 specialized Frenatas. In some of the 

 more generalized Frenatas, as the 

 Fig. 718.— Pupa of a moth. Nepticulidas, and in the Heliozelidae, 



the appendages are all free ; between 

 this condition and that of the truly obtected pupa of the more 

 specialized Frenatas, various intergrades exist. 



The pupae of this order vary also in the number of segments of the 

 body that are movable. The eighth, ninth, and tenth abdominal seg- 

 ments are always fixed. All of the other segments are movable in 

 the most generalized forms, and all are fixed in the most specialized 

 forms; there are various intergrades between these two extremes. 

 Different pupae of this order differ also in various other ways, 

 thus affording characters that are of taxonomic importance. It is 

 only recently that these characters have been used in an extended 

 manner. A pioneer paper in this field is that of Miss Edna Mosher 



More than nine thousand species of Lepidoptera are known to 

 occur in America north of Mexico. These represent two suborders 

 and seventy families. 



In popular language the Lepidoptera includes two quite distinct 

 groups of insects, the moths and the butterflies. Under the term 

 moths are included all of the members of the first suborder, the 

 Jugatae, and the larger number of the families of the second suborder, 

 the Frenatas; under the term butterflies are included the remaining 

 families of the suborder Frenatae. These two groups are distinguished 

 as follows. 



The moths. — These are the insects that are commonly called millers. 

 Most of the species fly by night and are frequently attracted to lights. 

 When at rest the wings are either wrapped around the body, or 

 spread horizontally, or folded roof-like on the abdomen; except 

 in a few cases they are not held in a vertical position above the body. 

 The antennas of moths are of various forms; they are usually thread- 



