44 



rougli, with a lew pn)iniiieii( tubercles, in size and form resembling the scales 

 left by the iiilling-otl' of Ihe leaves of the juniper. 



That this is an illustration of protective mimicry, of service to tlie species, 

 seems not unlikely. There are so many cases of this sort among the larvje of 

 this family that it seems unnecessary to adduce other examples. 



§ 14. — Terminology. 



In describing the head, the term '■\front" applies to the region in front 

 of the insertion of the anteniise, while the term '■'vertex^'' applies to the por- 

 tion above and behind the insertion of the antenna?. 



As regards the venation, the term '■'venule''' is applied to the branches of 

 the n)ain veins. The branches are numbered from the first one thrown off 

 to tlie last, going from the costa of the wing Imckwards (the costa being 

 regarded as the front edge of the wings when expanded, as in flight). The 

 costa is tlie front edge of tlie wing; the outer edge is situated between the 

 apex and the inner angle; the latter situated at the end of the internal vein; 

 while the innei- edge extends from near the end of the internal vein to the 

 insertion of the wing. Of the discal vein (which primarily consists of two 

 veins), the portion sent off" from the subcostal vein is called the anterior discal, 

 and the venule thrown off from the median vein is called ihc posterior discal. 

 The vein originating from the point of union of these two veins is called the 

 independent vein by French authors. 



Of the markings on the wings, there are often four or five lines, the inner 

 of which is called the basal, the second the inedian or intradiscal, and the third 

 the extradiscal; while there are often a submarginal line and a marginal line, 

 the latter interrupted by tlie venules. See also the explanations of the plates. 



