ANTENNAE OF LKPIDOPTERA. 43 



of the males, while in most of the other Satuniiimi they are much 

 less specialized. 



The Hemileuriche ('xliil)it a line of (level()i)mciit distinct from that 

 of the Bombycidie ou the one hantl in having the pectinations dorsal 

 instead of ventral, and from the Citheroniidte and Saturniidie on 

 the other in having a single pair of pectinations to a segment. Thus 

 it ap])ears that they belonged to the branch which produced the 

 latter families after it had separated from the branch giving rise to 

 the Bombycidce. 



The ('itheroniidie and the Saturniidie have followed the same line 

 of development in that they botii have two })airs of dorsal pectina- 

 tions to a segment. The first family has not progressed so far as the 

 second ; its members do not have their antenme pectinate throughout. 

 The antennte (}f these families show a high degree of <levelopment 

 also in the arrangement of the hairs of the third type. The spaces 

 between the pectinations are nearly filled by long, interlacing hairs, 

 which are regularly arranged in a distinct line of from two to three 

 rows extending continuously from the apex of one pectination along 

 the dorso-lateral surface of the segment to the apex of the other 

 pectination of the same side. Fig. 54 represents the arrangement 

 in I)ri/ocampa rubicunda. Still another feature showing remarkable 

 development of sense-organ., is exhibited in the higher forms, espe- 

 cially in Tropcea and Sum la of the Saturniidte. This is the nmlti- 

 plication of cones. While in nearly all other moths cones are 

 limited to one or at most two to a segment, we here find them liter- 

 ally heaped up on the ventro-distal edge of the segments of the 

 distal portion of the antennse ; and on the pectinations also there 

 are often several either at the apex or along the i)ectination at va- 

 rious intervals. Fig. 7 shows this condition in the antenna of Tropcea 

 luna. 



The family Saturniidie is interesting in the series of form it pre- 

 sents. The genera Coloradia, Automeris, Callosaturnia, Tropcea, 

 Telea, Callosamia, Philosamia and Samia, present a regular and 

 progressive series. The following table will serve to separate the 

 antenn;o of the members of this family : 



SATURNIID^. 

 A. Antenuse of female with single pair of i)eclinations to a segment. 



B. Antennaj of male with distal pair of pectinations shorter than the iiroximal. 

 C. Distal pair not more than half the k'ligth of the i>roximal.. .Coloradia. 

 CC. Distal pair but little shorter Automeris. 



TR.^NS. .^M. ENT. SOC. XXIII. M.\RCH, 1896 



